Method and apparatus for measuring carbon emission of district heating system, electronic device, and medium

ABSTRACT

The present disclosure discloses a method and apparatus for measuring carbon emission of a district heating system, an electronic device, and a medium. The method includes: obtaining a steady carbon emission amount of a current district heating system using a pre-trained steady carbon emission flow model; obtaining a dynamic carbon emission amount of the current district heating system using a pre-trained dynamic carbon emission flow model; and counting a carbon emission amount of the current district heating system based on the steady carbon emission amount and the dynamic carbon emission amount. Therefore, the present disclosure can effectively identify carbon emission details of each link of a source, a grid, and a load of the district heating system, clarify carbon emission responsibilities on both a source side and a load side, and realize accurate measurement of carbon emission of the district heating system, which has high application value.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims priority to Chinese Patent Application No. 202210016549.4, filed on Jan. 7, 2022, the entire content of which is incorporated herein by reference.

FIELD

The present disclosure relates to the field of low-carbon technologies for energy systems, and more particularly, to a method and apparatus for measuring carbon emission of a district heating system, an electronic device, and a medium.

BACKGROUND

Currently, most countries around the world have reached a consensus on achieving carbon neutrality by the middle of this century. However, time of peak carbon dioxide emissions in China is closely related to a decline speed of national coal consumption. In particular, since China's conventional heating method is mainly based on burning coal, and residential heating is a relative “hard constraint”, district heating is still one of the largest coal consumption and carbon emission industries in China. The above facts determine that carbon reduction of a district heating system is not only a source-side task, but also requires cooperation of the whole chain of “source-grid-load”. Real-time, accurate, and comprehensive carbon emission measurement is a basis and prerequisite for grasping a status and a trend of carbon emission of the district heating system, exploring potential in carbon emission reduction, guiding users to reduce carbon emission interactively, and promoting an upgrade of the district heating system into a low-carbon district heating system.

To better combine characteristics of an energy system with the concept of low-carbon development and expand the research on low-carbon energy technologies, it is necessary to understand and analyze carbon emission problems in the energy system, especially the district heating system, from a “carbon perspective”. In recent years, in the international import and export trade network, some scholars found that most carbon emission during full life cycles of imported and exported goods are concentrated in production while no carbon emission is generated in use, which is unfair to export-oriented countries and regions. Based on this, a transfer of coupling the carbon emission from an exporting country to an importing country should be performed in trade and logistics of international imported and exported goods to clarify the carbon emission responsibility that the importing country should bear due to goods consumption aiming to obtain utility. Therefore, a new concept of carbon emission flow is derived. In the district heating system, different supply technologies have different carbon emission characteristics, but there is no difference in a power flow and carbon emission that are generated by the different supply technologies. In this way, the carbon emission flow has a much easier and more flexible application space in the district heating system than in the trade and logistics. Therefore, the district heating system has a good foundation for constructing a theoretical system of the carbon emission flow.

At the present stage of research on low-carbon technologies for energy systems, the macro-statistical method and the full life cycle method are usually used. However, since these source-side calculation methods span a large time scale, involve a too macroscopic spatial scope of the system, and can only provide a total amount of carbon emission, which cannot effectively identify details of carbon emission in each link of the source, the grid, and the load, leading to problems such as unreasonable allocation of carbon emission responsibilities between source and load sides. Therefore, it is difficult to guide optimal low-carbon operation of the district heating system.

SUMMARY

The present disclosure provides a method and apparatus for measuring carbon emission of a district heating system, an electronic device, and a medium, capable of effectively identifying carbon emission details of each link of a source, a grid, and a load of the district heating system, clarifying carbon emission responsibilities on both a source side and a load side, and realizing accurate measurement of carbon emission of the district heating system, which has high application value.

Embodiments in a first aspect of the present disclosure provide a method for measuring carbon emission of a district heating system. The method includes: obtaining a steady carbon emission amount of a current district heating system using a pre-trained steady carbon emission flow model, in which the pre-trained steady carbon emission flow model is constructed based on a pipeline carbon flow rate, network loss carbon emission, a nodal carbon flow density, a pipeline carbon flow density, a heat source carbon flow rate, and a heat load carbon flow rate of the current district heating system; obtaining a dynamic carbon emission amount of the current district heating system using a pre-trained dynamic carbon emission flow model, in which the pre-trained dynamic carbon emission flow model is constructed based on water element carbon flow rates at a plurality of time periods, actual outlet carbon flow rates of a pipeline at the plurality of time periods, network loss carbon flow rates at the plurality of time periods, and nodal carbon flow densities at the plurality of time periods of the current district heating system; and counting a carbon emission amount of the current district heating system based on the steady carbon emission amount and the dynamic carbon emission amount.

Optionally, in an embodiment of the present disclosure, the method further includes:

constructing the steady carbon emission flow model of the district heating system based on the pipeline carbon flow rate, the network loss carbon emission, the nodal carbon flow density, the pipeline carbon flow density, the heat source carbon flow rate, and the heat load carbon flow rate of the district heating system. The operation of constructing the steady carbon emission flow model of the district heating system based on the pipeline carbon flow rate, the network loss carbon emission, the nodal carbon flow density, the pipeline carbon flow density, the heat source carbon flow rate, and the heat load carbon flow rate of the district heating system is:

-   -   determining the pipeline carbon flow rate of the district         heating system including a carbon flow rate of a water supply         network and a carbon flow rate of a water return network, the         carbon flow rate of the water supply network being:

R _(k) ^(BHS,in)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,in) ,∀k∈Ω ^(BH)

R _(k) ^(BHS,out)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,out) ,∀k∈Ω ^(BH),

-   -   where R_(k) ^(BHS,in) and R_(k) ^(BHS,out) represent an inlet         carbon flow rate and an outlet carbon flow rate of a pipeline k         in the water supply network, respectively, unit: tCO₂/h; ρ_(k)         ^(BHS) represents a carbon flow density of the pipeline k in the         water supply network, unit: tCO₂/MWh; c represents a specific         heat capacity of water, unit: MWh/(kg·° C.); m_(k) ^(S)         represents a mass flow of the pipeline k in the water supply         network, unit: kg/h; T_(k) ^(S,in) and T_(k) ^(S,out) represent         an inlet temperature and an outlet temperature of the pipeline k         in the water supply network, unit: ° C.; and Ω^(BH) represents a         set of pipelines in the district heating system; and     -   the carbon flow rate of the water return network being:

R _(k) ^(BHR,in)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,in) ,∀k∈Ω ^(BH)

R _(k) ^(BHR,out)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,out) ,∀k∈Ω ^(BH),

-   -   where R_(k) ^(BHR,in) and R_(k) ^(BHR,out) represent an inlet         carbon flow rate and an outlet carbon flow rate of a pipeline k         in the water return network, respectively, unit: tCO₂/h; ρ_(k)         ^(BHR) represents a carbon flow density of the pipeline k in the         water return network, unit: tCO₂/h; m_(k) ^(R) represents a mass         flow of the pipeline k in the water return network, unit: kg/h;         and T_(k) ^(R,in) and T_(k) ^(R,out) represent an inlet         temperature and an outlet temperature of the pipeline k in the         water return network, unit: ° C.;     -   determining the network loss carbon emission of the district         heating system including a network loss carbon flow rate of the         water supply network and a network loss carbon flow rate of the         water return network, the operation of determining the network         loss carbon emission of the district heating system being:         -   determining a temperature difference of a pipeline in the             water supply network and a temperature difference of a             pipeline in the water return network:

T _(k) ^(S,Loss) =T _(k) ^(S,in) −T _(k) ^(S,out)

T _(k) ^(R,Loss) =T _(k) ^(R,in) −T _(k) ^(R,out),

-   -   -   where T_(k) ^(S,Loss) and T_(k) ^(R,Loss) represent a             temperature difference between both ends of the pipeline k             in the water supply network and a temperature difference             between both ends of the pipeline k in the water return             network, respectively, unit: ° C.; and         -   determining the network loss carbon flow rate of the water             supply network and the network loss carbon flow rate of the             water return network:

R _(k) ^(BHS,Loss)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,Loss) ,∀k∈Ω ^(BH)

R _(k) ^(BHR,Loss)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,Loss) ,∀k∈Ω ^(BH),

-   -   -   where R_(k) ^(BHS,Loss) and R_(k) ^(BHR,Loss) represent a             network loss carbon flow rate of the pipeline k in the water             supply network and a network loss carbon flow rate of the             pipeline k in the water return network, respectively, unit:             tCO₂/h;

    -   determining the nodal carbon flow density of the district         heating system, the operation of determining the nodal carbon         flow density of the district heating system including:         -   determining, for each node in the district heating system,             that conservation of mass and conservation of energy are             satisfied at the node:

${m_{n}^{S} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}m_{k}^{S}}},{\forall{n \in \Omega^{NH}}}$ ${{T_{n}^{S}m_{n}^{S}} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}{T_{k}^{S,{out}}m_{k}^{S}}}},{\forall{n \in \Omega^{NH}}},$

-   -   -   where m_(n) ^(S) represents a total mass flow flowing             through a node n in the water supply network, unit: kg/h;             Ω_(n) ^(BH+) represents a set of injection pipelines at the             node n in the water supply network; Ω^(NH) represents a set             of nodes in the district heating system; and T_(n) ^(S)             represents a water flow temperature of the node n in the             water supply network, unit: ° C.;         -   determining, for each node in the district heating system,             that conservation of carbon emission is satisfied at the             node, a carbon flow rate of the node n being equal to a sum             of outlet carbon flow rates of all the injection pipelines             and network loss carbon flow rates allocated to the             injection pipelines;

${R_{n}^{NHS} = {{\sum\limits_{k \in \Omega_{n}^{{BH} +}}\left( {R_{k}^{{BHS},{out}} + {XR_{k}^{{BHS},{Loss}}}} \right)} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}{\rho_{k}^{BHS}{{cm}_{k}^{S}\left( {T_{k}^{S,{out}} + {XT_{k}^{S,{Loss}}}} \right)}}}}},{\forall{n \in \Omega^{NH}}},$

-   -   -   where R_(n) ^(NHS) represents the carbon flow rate of the             node n in the water supply network, unit: tCO₂/h; and X             represents an allocating coefficient of a network loss             carbon flow rate of an injection pipeline;         -   determining a carbon flow density of the node n in the water             supply network:

${\rho_{n}^{NHS} = {\frac{R_{n}^{NHS}}{cm_{n}^{S}T_{n}^{S}} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{\rho_{k}^{BHS}{m_{k}^{S}\left( {T_{k}^{S,{out}} + {XT_{k}^{S,{Loss}}}} \right)}}}{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{m_{k}^{S}T_{k}^{S,{out}}}}}},{\forall{n \in \Omega^{NH}}},$

-   -   -   where ρ_(n) ^(NHS) represents the carbon flow density of the             node n in the water supply network, unit: tCO₂/MWh; and         -   determining a carbon flow density of the node n in the water             return network:

${\rho_{n}^{NHR} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{\rho_{k}^{BHR}{m_{k}^{R}\left( {T_{k}^{R,{out}} + {XT}_{k}^{R,{Loss}}} \right)}}}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{m_{k}^{R}T_{k}^{R,{out}}}}},{\forall{n \in \Omega^{NH}}},$

-   -   -   where ρ_(n) ^(NHR) represents the carbon flow density of the             node n in the water return network, unit: tCO₂/MWh; and             Ω_(n) ^(BH−) represents a set of outflow pipelines at the             node n in the water supply network;

    -   determining the pipeline carbon flow density of the district         heating system:

ρ_(k) ^(BHS)=ρ_(n) ^(NHS) ,n=Γ _(k) ^(NH+) ,∀k∈Ω ^(BH)

ρ_(k) ^(BHR)=ρ_(n) ^(NHR) ,n=Γ _(k) ^(NH−) ,∀k∈Ω ^(BH),

-   -   where Γ_(k) ^(NH+) and Γ_(k) ^(NH+) represent an injection node         and an outflow node of the pipeline k in the water supply         network, respectively;     -   determining the heat source carbon flow rate of the district         heating system, the operation of determining the heat source         carbon flow rate of the district heating system including:         -   determining a heat output of a heat source:

Q _(i) =cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(i) ^(NH) ,∀i∈Ω ^(GH),

-   -   -   where Q_(i) represents a heat output of a heat source i,             unit: MW; Γ_(i) ^(NH) represents a node where the heat             source i is located; and Ω^(GH) represents a set of heat             sources; and         -   determining that conservation of carbon emission at a heat             source node is satisfied:

ρ_(n) ^(NHS) cm _(n) ^(S) T _(n) ^(S)=ρ_(i) ^(GH) Q _(i)+ρ_(n) ^(NHR) cm _(n) ^(S) T _(n) ^(R) ,n=δ _(i) ^(NH) ,∀i∈Ω ^(GH),

-   -   -   where ρ_(i) ^(GH) represents a carbon flow density of the             heat source i, unit: tCO₂/MWh; and

    -   determining the heat load carbon flow rate of the district         heating system, the operation of determining the heat load         carbon flow rate of the district heating system including:         -   determining a heat load demand:

q _(j) =cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R))n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH),

-   -   -   where q_(j) represents a heat demand of a heat load j, unit:             MW; Γ_(j) ^(NH) represents a node where the heat load j is             located; and Ω^(LH) represents a set of heat loads;         -   determining a carbon flow density of a heat load node:

ρ_(n) ^(NHR)=ρ_(n) ^(NHS) ,n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH); and

-   -   -   determining the heat load carbon flow rate:

R _(j) ^(LH)=ρ_(n) ^(NHS) q _(j)=ρ_(n) ^(NHS) cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH),

-   -   -   where R_(j) ^(LH) represents a carbon flow rate of the heat             load j, unit: tCO₂/h.

Optionally, in an embodiment of the present disclosure, the method further includes: calculating a matrix representation of the steady carbon emission flow model of the district heating system.

Optionally, in an embodiment of the present disclosure, the operation of calculating the matrix representation of the steady carbon emission flow model of the district heating system includes: constructing a branch heat flow matrix, a branch network loss matrix, and a nodal heat flow flux matrix of the district heating system; and calculating a nodal carbon flow density vector of a heat network, and then calculating a branch carbon flow rate matrix, a network loss carbon flow rate matrix, and a load carbon flow rate vector of each of the water supply network and the water return network.

Optionally, in an embodiment of the present disclosure, the operation of calculating the matrix representation of the steady carbon emission flow model of the district heating system includes:

constructing the branch heat flow matrix of the district heating system including a branch heat flow matrix of the water supply network and a branch heat flow matrix of the water return network, in which the operation of constructing the branch heat flow matrix of the district heating system includes:

-   -   determining elements of the branch heat flow matrix of the water         supply network:

Q _(B,ij) ^(S) =cm _(k) ^(S) T _(k) ^(S,out) ,Q _(B,ji) ^(S)=0,

-   -   where Q_(B,ij) ^(S) and Q_(B,ji) ^(S) represent elements in a         branch heat flow matrix Q_(B) ^(S) of the water supply network;         and     -   determining elements of the branch heat flow matrix of the water         return network:

Q _(B,ij) ^(R) =cm _(k) ^(R) T _(k) ^(R,out) ,Q _(B,ji) ^(R)=0,

-   -   where Q_(B,ij) ^(R) and Q_(B,ji) ^(R) represent elements in a         branch heat flow matrix Q_(B) ^(R) of the water return network;

constructing the branch network loss matrix of the district heating system including a branch network loss matrix of the water supply network and a branch network loss matrix of the water return network, in which the operation of constructing the branch network loss matrix of the district heating system includes:

-   -   determining elements of the branch network loss matrix of the         water supply network:

Q _(BL,ij) ^(S) =cm _(k) ^(S) T _(k) ^(S,Loss) ,Q _(BL,ji) ^(S)=0,

-   -   where Q_(BL,ij) ^(S) and Q_(BL,ji) ^(S) represent elements in a         branch network loss matrix Q_(BL) ^(S) of the water supply         network; and     -   determining elements of the branch network loss matrix of the         water return network:

Q _(BL,ij) ^(R) =cm _(k) ^(R) T _(k) ^(R,Loss) ,Q _(BL,ji) ^(R)=0,

-   -   where Q_(BL,ij) ^(R) and Q_(BL,ji) ^(R) represent elements in a         branch network loss matrix Q_(BL) ^(R) of the water return         network;

constructing the nodal heat flow flux matrix of the district heating system including a nodal heat flow flux matrix of the water supply network and a nodal heat flow flux matrix of the water return network, in which the operation of constructing the nodal heat flow flux matrix of the district heating system includes:

-   -   determining, for a node in no connection to the heat source, the         nodal heat flow flux matrix of the water supply network:

Q _(N) ^(S)=diag{ζ_(N) _(NH) Q _(B) ^(S)}

-   -   where Q_(N) ^(S) represents the nodal heat flow flux matrix of         the water supply network; ζ_(N) _(NH) represents a coefficient         matrix of a branch heat flow; and N_(NH) represents a number of         nodes of the district heating system;     -   determining, for a node in no connection to the heat source, the         nodal heat flow flux matrix of the water return network:

Q _(N) ^(R)=diag{ζ_(N) _(NH) Q _(B) ^(R)},

-   -   where Q_(N) ^(R) represents the nodal heat flow flux matrix of         the water return network;     -   determining, for a node connected to the heat source, a nodal         integrated energy flow flux matrix:

{circumflex over (Q)} _(N) ^(S)=diag{ζ_(N) _(NH) Q _(B) ^(S)+ζ_(N) _(GH) Q _(G)},

-   -   where {circumflex over (Q)}_(N) ^(S) represents the nodal         integrated energy flow flux matrix; ζ_(N) _(GH) represents a         coefficient matrix of a heat flow injected by the heat source;         and N_(GH) represents a number of heat sources of the district         heating system;

determining, for all nodes, that a total injected carbon emission of the nodes is equal to a sum of injected carbon flow rates of all branches connected to the nodes:

Q _(N) ^(S)ρ^(NHS)=(Q _(B) ^(S) +XQ _(BL) ^(S))^(T)ρ^(NHS)

Q _(N) ^(R)ρ^(NHR)=(Q _(B) ^(R) +XQ _(BL) ^(R))^(T)ρ^(NHR),

where ρ^(NHS) represents a matrix formed by the carbon flow density ρ_(n) ^(NHS) of the node n in the water supply network; and ρ^(NHR) represents a matrix formed by the carbon flow density ρ_(n) ^(NHR) of the node n in the water return network;

determining, for the heat load node, that the heat load node has an equal carbon flow density in the water supply network and the water return network:

Bρ ^(NHS) =Bρ ^(NHR),

where B represents a heat load-node association matrix, when the heat load j is connected to the node n, B_(jn)=1, otherwise B_(jn)=0;

determining, for the heat source node, a matrix relation of the heat source node based on a conservation of carbon emission as:

C{circumflex over (Q)} _(N) ^(S)ρ^(NHS) =CQ _(N) ^(R)ρ^(NHR) +Q _(G) ^(T)ρ^(GH),

where C represents a 0-1 matrix associated with the heat source node, when the node n is connected to the heat source, C_(nn)=1, otherwise C_(nn)=0;

determining the nodal carbon flow density vector of the heat network as:

${\begin{bmatrix} \rho^{NHS} \\ \rho^{NHR} \end{bmatrix} = {\begin{bmatrix} {Q_{N}^{S} - \left( Q_{B}^{S} \right.} & \left. {{+ X}Q_{BL}^{S}} \right)^{T} & 0 \\  & 0 & {Q_{N}^{R} - \left( {Q_{B}^{R} + {XQ_{BL}^{R}}} \right)^{T}} \\  & B & {- B} \\  & {C{\overset{\hat{}}{Q}}_{N}^{S}} & {{- C}Q_{N}^{R}} \end{bmatrix}^{- 1}\begin{bmatrix} 0 \\ 0 \\ 0 \\ {Q_{G}^{T}\rho^{GH}} \end{bmatrix}}};$

and

calculating the branch carbon flow rate matrix, the network loss carbon flow rate matrix, and the load carbon flow rate vector of each of the water supply network and the water return network.

Optionally, in an embodiment of the present disclosure, the method further includes:

constructing the dynamic carbon emission flow model of the district heating system based on the water element carbon flow rates at the plurality of time periods, the actual outlet carbon flow rates of the pipeline at the plurality of time periods, the network loss carbon flow rates at the plurality of time periods, and the nodal carbon flow densities at the plurality of time periods. The operation of constructing the dynamic carbon emission flow model of the district heating system based on the water element carbon flow rates at the plurality of time periods, the actual outlet carbon flow rates of the pipeline at the plurality of time periods, the network loss carbon flow rates at the plurality of time periods, and the nodal carbon flow densities at the plurality of time periods is:

determining the water element carbon flow rates at the plurality of time periods:

${{\overset{\sim}{R}}_{k,t}^{{BHS},{out}} = {\frac{R_{k,{t - \delta_{k,t}}}^{{BHS},{in}}\left( {B_{k,t} - {\sigma M_{k}}} \right)}{\left( {m_{k,{t - \delta_{k,t}}}^{S}\Delta t} \right)} + {\sum\limits_{\tau = {t - \varphi_{k,t} + 1}}^{t - \delta_{k,t} - 1}R_{k,\tau}^{{BHS},{in}}} + \frac{R_{k,{t - \delta_{k,t}}}^{{BHS},{in}}\left( {{m_{k,t}^{S}\Delta t} + {\sigma M_{k}} - A_{k,t}} \right)}{\left( {m_{k,{t - \varphi_{k,t}}}^{S}\Delta t} \right)}}},$

where R_(k,t) ^(BHS,out) represents a water element carbon flow rate at a time period t; σ represents a density of water; M_(k) represents a volume of the pipeline k; φ_(k,t) represents an injection time period of an earliest water element component contained in a water flow flowing out of the pipeline k at the time period t; δ_(k,t) represents an injection time period of a latest water element component contained in the water flow flowing out of the pipeline k at the time period t; A_(k,t) represents a total injection water flow amount for φ_(k,t) time periods before the time period t; B_(k,t) represents a total injection water flow amount from a time period t−δ_(k,t) to the time period t; and expressions for A_(k,t) and B_(k,t) are:

$A_{k,t} = \left\{ {\begin{matrix} {{\sum\limits_{\tau = {t - \varphi_{k,t} + 1}}^{t}{m_{k,\tau}^{S}\Delta t}},} & {\varphi_{k,t} \geq {\delta_{k,t} + 1}} \\ {B_{k,t},} & {\varphi_{k,t} < {\delta_{k,t} + 1}} \end{matrix},} \right.$ ${B_{k,t} = {\sum\limits_{\tau = {t - \delta_{k,t}}}^{t}{m_{k,\tau}^{S}\Delta t}}};$

and

determining the actual outlet carbon flow rates of the pipeline at the plurality of time periods and the network loss carbon flow rates at the plurality of time periods, the operation of determining the actual outlet carbon flow rates of the pipeline at the plurality of time periods and the network loss carbon flow rates at the plurality of time periods including:

calculating an actual temperature of an outlet water flow of the pipeline based on a conveying loss of the pipeline:

${T_{k,t}^{S,{out}} = {{\overset{˜}{T}}_{k,t}^{S,{out}}\exp\left( {- \frac{\lambda L_{k}}{cm_{k,t}^{S}}} \right)}},$

-   -   where T_(k,t) ^(S,out) represents the actual temperature of the         outlet water flow of the pipeline; {tilde over (T)}_(k,t)         ^(S,out) represents a weighted average of temperatures of         injection water flows at previous time periods; λ represents a         thermal conductivity coefficient of the pipeline; and L_(k)         represents a length of the pipeline k;     -   determining an actual outlet carbon flow rate of the pipeline at         the time period t:

$\rho_{n,t}^{NHR} = {\frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}\left( {R_{k,t}^{{BHR},{out}} + {XT}_{k,t}^{{BHR},{Loss}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{m_{k,t}^{R}T_{k,t}^{R,{out}}}}.}$

and

-   -   determining a network loss carbon flow rate of the pipeline at         the time period t:

${R_{k,t}^{{BHS},{Loss}} = {{\overset{\sim}{R}}_{k,t}^{{BHS},{Loss}}\left( {1 - \frac{T^{S,{out}}}{{\overset{\sim}{T}}_{k,t}^{S,{out}}}} \right)}};$

determining the nodal carbon flow densities at the plurality of time periods:

${\rho_{n,t}^{NHS} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} +}}\left( {R_{k,t}^{{BHS},{out}} + {XR_{k,t}^{{BHS},{Loss}}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{cm_{k,t}^{S}T_{k,t}^{S,{out}}}}};$

and

determining, for the water return network, the nodal carbon flow densities at the plurality of time periods:

$\rho_{n,t}^{NHR} = {\frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}\left( {R_{k,t}^{{BHR},{out}} + {XR_{k,t}^{{BHR},{Loss}}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{cm_{k,t}^{R}T_{k,t}^{R,{out}}}}.}$

Embodiments in a second aspect of the present disclosure provide an apparatus for measuring carbon emission of a district heating system. The apparatus includes: a plurality of heat source-side carbon meters, in which each of the plurality of heat source-side carbon meters is connected to a heat source and configured to measure heat source-side carbon emission; a plurality of heat pipeline carbon meters, in which each of the plurality of heat pipeline carbon meters is connected to a heat pipeline and the heat source-side carbon meter, and the heat pipeline carbon emission meter is configured to measure heat pipeline carbon emission; a plurality of user-side carbon meters, in which each of the plurality of user-side carbon meters has one end connected to a heat user end and another end connected to the heat pipeline carbon meter, and is configured to obtain a carbon potential of a node where a user is located and obtain a carbon emission amount resulted from heat consumption of the user; and a central server, in which the central server is connected to the plurality of heat source-side carbon meters and the plurality of heat pipeline carbon meters, and configured to calculate a carbon emission intensity of the heat source based on coal consumption data of the heat source and an emission coefficient of the coal, calculate a distribution of a carbon emission flow in the heat pipeline, and calculate a carbon emission amount corresponding to a pipeline connected to the node based on data of the heat pipeline carbon meter.

Optionally, in an embodiment of the present disclosure, each of the heat source-side carbon meter, the heat pipeline carbon meter, and the user-side carbon meter is further configured to display in real time a result of the carbon emission of the district heating system calculated by the central server.

Embodiments in a third aspect of the present disclosure provide an electronic device. The electronic device includes: a memory; a processor; and a computer program stored in the memory and executable on the processor. The processor, when executing the computer program, performs the method for measuring the carbon emission of the district heating system according to any of the above embodiments.

Embodiments in a fourth aspect of the present disclosure provide a computer-readable storage medium. The computer-readable storage medium stores a computer program. The computer program, when executed by a processor, performs the method for measuring the carbon emission of the district heating system according to any of the above embodiments.

Embodiments of the present disclosure can provide the following advantageous effects.

1) The steady carbon emission flow model of the district heating system of the present disclosure can identify carbon emission details of each link of a source, a grid, and a load of the district heating system, which includes the pipeline carbon flow rate, the network loss carbon emission, the nodal carbon flow density, the pipeline carbon flow density, the heat source carbon flow rate, and the heat load carbon flow rate. In this way, the “carbon reduction” task at a source side can be reasonably and effectively allocated to a chain of “source-grid-load” to further clarify the responsibility of carbon emission in each link of the district heating system.

2) The present disclosure also constructs the dynamic carbon emission flow model of the district heating system by taking into account characteristics of dynamic conveying of the district heating system, which can enable a current situation and a trend of the carbon emission of the district heating system to be grasped accurately and comprehensively in real time.

3) For a carbon meter system of the present disclosure, with the help of a data collection, processing, and display system, a calculation result of the carbon meter system can be displayed intuitively to heat users, which is conducive to further exploring potential of the district heating system in carbon emission reduction, guides the users to reduce carbon emission interactively, and has high application value.

Additional aspects and advantages of the present disclosure will be provided at least in part in the following description, or will become apparent at least in part from the following description, or can be learned from practicing of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional aspects and advantages of the present disclosure will become more apparent and more understandable from the following description of embodiments taken in conjunction with the accompanying drawings.

FIG. 1 is a flowchart illustrating a method for measuring carbon emission of a district heating system according to an embodiment of the present disclosure.

FIG. 2 is a schematic diagram showing a framework structure of a method for measuring carbon emission of a district heating system according to an embodiment of the present disclosure.

FIG. 3 is a schematic diagram showing a result of solving a steady carbon emission flow of a district heating system according to an embodiment of the present disclosure.

FIG. 4 is a schematic diagram showing a result of solving a dynamic carbon emission flow of a district heating system according to an embodiment of the present disclosure.

FIG. 5 is an example diagram of an apparatus for measuring carbon emission of a district heating system according to an embodiment of the present disclosure.

FIG. 6 is a schematic diagram showing a structure of an electronic device according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

The embodiments of the present disclosure will be described in detail below with reference to examples thereof as illustrated in the accompanying drawings, throughout which same or similar elements, or elements having same or similar functions, are denoted by same or similar reference numerals. The embodiments described below with reference to the drawings are illustrative only, and are intended to explain, rather than limiting, the present disclosure.

FIG. 1 is a flowchart illustrating a method for measuring carbon emission of a district heating system according to an embodiment of the present disclosure.

As illustrated in FIG. 1 , the method for measuring the carbon emission of the district heating system includes actions at blocks S101 to S103.

At block S101, a steady carbon emission amount of a current district heating system is obtained using a pre-trained steady carbon emission flow model. The pre-trained steady carbon emission flow model is constructed based on a pipeline carbon flow rate, network loss carbon emission, a nodal carbon flow density, a pipeline carbon flow density, a heat source carbon flow rate, and a heat load carbon flow rate of the current district heating system.

It should be understood that, according to the embodiments of the present disclosure, the steady carbon emission flow model of the district heating system is constructed based on the carbon emission flow theory. The constructed steady carbon emission flow model of the district heating system is used to obtain the steady carbon emission amount of the current district heating system.

In some embodiments, the steady carbon emission flow model of the district heating system is formed by the pipeline carbon flow rate, the network loss carbon emission, the nodal carbon flow density, the pipeline carbon flow density, the heat source carbon flow rate, and the heat load carbon flow rate of the district heating system. The operation of forming the steady carbon emission flow model of the district heating system includes the following actions.

1-1) In a case of a steady carbon emission flow, no convergence or divergence of a water flow is found in a single pipeline since a conveying delay is not considered. Therefore, carbon flow densities at a pipeline inlet and a pipeline outlet are equal and uniformly defined as a carbon flow density of the pipeline. An inlet carbon flow rate of the pipeline is equal to a product of an inlet energy flow and the pipeline carbon flow density. An outlet carbon flow rate of the pipeline is equal to a product of an outlet energy flow and the pipeline carbon flow density. The pipeline carbon flow rate of the district heating system is determined. The pipeline carbon flow rate of the district heating system includes a carbon flow rate of a water supply network and a carbon flow rate of a water return network. The operation of determining the pipeline carbon flow rate of the district heating system includes the following actions at 1-1-1) and 1-1-2).

1-1-1) The carbon flow rate of the water supply network is determined. An expression of the carbon flow rate of the water supply network is:

R _(k) ^(BHS,in)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,in) ,∀k∈Ω ^(BH)

R _(k) ^(BHS,out)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,out) ,∀k∈Ω ^(BH)  (1)

where R_(k) ^(BHS,in) and R_(k) ^(BHS,out) represent an inlet carbon flow rate and an outlet carbon flow rate of a pipeline k in the water supply network, respectively, unit: tCO₂/h; ρ_(k) ^(BHS) represents a carbon flow density of the pipeline k in the water supply network, unit: tCO₂/MWh; c represents a specific heat capacity of water, unit: MWh/(kg·° C.); m_(k) ^(S) represents a mass flow of the pipeline k in the water supply network, unit: kg/h; T_(k) ^(S,in) and T_(k) ^(S,out) represent an inlet temperature and an outlet temperature of the pipeline k in the water supply network, unit: ° C.; and Ω^(BH) represents a set of pipelines in the district heating system.

1-1-2) The carbon flow rate of the water return network is determined as follows:

R _(k) ^(BHR,in)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,in) ,∀k∈Ω ^(BH)

R _(k) ^(BHR,out)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,out) ,∀k∈Ω ^(BH)  (2),

where R_(k) ^(BHR,in) and R_(k) ^(BHR,out) represent an inlet carbon flow rate and an outlet carbon flow rate of a pipeline k in the water return network, respectively, unit: tCO₂/h; ρ_(k) ^(BHR) represents a carbon flow density of the pipeline k in the water return network, unit: tCO₂/h; m_(k) ^(R) represents a mass flow of the pipeline k in the water return network, unit: kg/h; and T_(k) ^(R,in) and T_(k) ^(R,out) represent an inlet temperature and an outlet temperature of the pipeline k in the water return network, unit: ° C.

1-2) A heat network bears a large conveying loss, which causes additional carbon emission. The network loss carbon emission of the district heating system is determined. The network loss carbon emission of the district heating system includes a network loss carbon flow rate of the water supply network and a network loss carbon flow rate of the water return network. The operation of determining the network loss carbon emission of the district heating system includes the following actions at 1-2-1) and 1-2-2).

1-2-1) A loss in the heat network is mainly resulted from a temperature loss of a water flow in a pipeline. Therefore, the network loss carbon emission mainly depends on a temperature difference between two ends of the pipeline. A temperature difference of a pipeline in the water supply network and a temperature difference of a pipeline in the water return network are determined as follows:

T _(k) ^(S,Loss) =T _(k) ^(S,in) −T _(k) ^(S,out)

T _(k) ^(R,Loss) =T _(k) ^(R,in) −T _(k) ^(R,out)  (3),

where T_(k) ^(S,Loss) and T_(k) ^(R,Loss) represent a temperature difference between both ends of the pipeline k in the water supply network and a temperature difference between both ends of the pipeline k in the water return network, respectively, unit: ° C.

1-2-2) The network loss carbon flow rate of the water supply network and the network loss carbon flow rate of the water return network are determined as follows:

R _(k) ^(BHS,Loss)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,Loss) ,∀k∈Ω ^(BH)

R _(k) ^(BHR,Loss)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,Loss) ,∀k∈Ω ^(BH)  (4),

where R_(k) ^(BHS,Loss) and R_(k) ^(BHR,Loss) represent a network loss carbon flow rate of the pipeline k in the water supply network and a network loss carbon flow rate of the pipeline k in the water return network, respectively, unit: tCO₂/h.

1-3) For each node in the heat network, convergence of water flows from several pipelines may exist. Conservation of mass and conservation of energy are satisfied at the node. The nodal carbon flow density of the district heating system is determined. The operation of determining the nodal carbon flow density of the district heating system includes the following actions at 1-3-1), 1-3-2), 1-3-3) and 1-3-4).

1-3-1) For each node in the district heating system, it is determined that conservation of mass and conservation of energy are satisfied at the node:

$\begin{matrix} {\begin{matrix} {{m_{n}^{S} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}m_{k}^{S}}},{\forall{n \in \Omega^{NH}}}} \\ {{{T_{n}^{S}m_{n}^{S}} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}{T_{k}^{S,{out}}m_{k}^{S}}}},{\forall{n \in \Omega^{NH}}}} \end{matrix},} & (5) \end{matrix}$

where m_(n) ^(S) represents a total mass flow flowing through a node n in the water supply network, unit: kg/h; Ω_(n) ^(BH+) represents a set of injection pipelines at the node n in the water supply network; Ω^(NH) represents a set of nodes in the district heating system; T_(n) ^(S) represents a water flow temperature of the node n in the water supply network, unit: ° C.

1-3-2) For each node in the district heating system, conservation of carbon emission is satisfied at the node. In this way, a carbon flow rate of the node n is equal to a sum of outlet carbon flow rates of all the injection pipelines and network loss carbon flow rates allocated to the injection pipelines, which is expressed as:

$\begin{matrix} {{R_{n}^{NHS} = {{\sum\limits_{k \in \Omega_{n}^{{BH} +}}\left( {R_{k}^{{BHS},{out}} + {XR_{k}^{{BHS},{Loss}}}} \right)} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}{\rho_{k}^{BHS}{{cm}_{k}^{S}\left( {T_{k}^{S,{out}} + {XT_{k}^{S,{Loss}}}} \right)}}}}},{\forall{n \in \Omega^{NH}}},} & (6) \end{matrix}$

where R_(n) ^(NHS) represents the carbon flow rate of the node n in the water supply network, unit: tCO₂/h; and X represents an allocating coefficient of a network loss carbon flow rate of an injection pipeline.

1-3-3) A carbon flow density of the node n in the water supply network is determined as follows:

$\begin{matrix} {{\rho_{n}^{NHS} = {\frac{R_{n}^{NHS}}{cm_{n}^{S}T_{n}^{S}} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{\rho_{k}^{BHS}{m_{k}^{S}\left( {T_{k}^{S,{out}} + {XT_{k}^{S,{Loss}}}} \right)}}}{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{m_{k}^{S}T_{k}^{S,{out}}}}}},{\forall{n \in \Omega^{NH}}}} & (7) \end{matrix}$

where ρ_(n) ^(NHS) represents the carbon flow density of the node n in the water supply network, unit: tCO₂/MWh.

1-3-4) A carbon flow density of the node n in the water return network is determined as follows:

$\begin{matrix} {{\rho_{n}^{NHR} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{\rho_{k}^{BHR}{m_{k}^{R}\left( {T_{k}^{R,{out}} + {XT}_{k}^{R,{Loss}}} \right)}}}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{m_{k}^{R}T_{k}^{R,{out}}}}},{\forall{n \in \Omega^{NH}}},} & (8) \end{matrix}$

where ρ_(n) ^(NHR) represents the carbon flow density of the node n in the water return network, unit: tCO₂/MWh; and Ω^(BH−) represents a set of outflow pipelines at the node n in the water supply network.

1-4) Each pipeline in the water supply network and the water return network satisfies an energy allocation criterion. That is, the pipeline carbon flow density is equal to a carbon flow density of an injection node of a pipeline. The pipeline carbon flow density of the district heating system is determined as follows:

ρ_(k) ^(BHS)=ρ_(n) ^(NHS) ,n=Γ _(k) ^(NH+) ,∀k∈ΩBH

ρ_(k) ^(BHR)=ρ_(n) ^(NHR) ,n=θ _(k) ^(NH−) ,∀k∈Ω ^(BH)  (9),

where Γ_(k) ^(NH+) and Γ_(k) ^(NH+) represent an injection node and an outflow node of the pipeline k in the water supply network, respectively.

1-5) The heat source and the heat load are connection points of the water supply network and the water return network, through which a carbon emission flow of the water supply network and a carbon emission flow of the water return network can be connected to form a complete carbon emission flow of the heat network. The heat source carbon flow rate of the district heating system is determined. The operation of determining the heat source carbon flow rate of the district heating system includes the following actions at 1-5-1) and 1-5-2).

1-5-1) A heat output of a heat source is determined as follows:

Q _(i) =cm _(n) ^(S)(T _(n) ^(S) =T _(n) ^(R)),n=Γ _(i) ^(NH) ,∀i∈Ω ^(GH)  (10),

where Q_(i) represents a heat output of a heat source i, unit: MW; Γ_(i) ^(NH) represents a node where the heat source i is located; and Ω^(GH) represents a set of heat sources.

1-5-2) At a heat source node, conservation of carbon emission is also satisfied. That is, a carbon flow rate of water supply at the heat source node is equal to a sum of an injected carbon flow rate of the heat source and a carbon flow rate of water return at the heat source node. It is equivalent to that the heat source injects energy into the heat network while injecting corresponding carbon emission. A ratio between the injected energy and the injected carbon emission is the carbon flow density of the heat source. In some embodiments,

ρ_(n) ^(NHS) cm _(n) ^(S) T _(n) ^(S)=ρ_(i) ^(GH) Q _(i)+ρ_(n) ^(NHR) cm _(n) ^(S) T _(n) ^(R) ,n=Γ _(i) ^(NH) ,∀i∈Ω ^(GH)  (11),

where ρ_(i) ^(GH) represents a carbon flow density of the heat source i, unit: tCO₂/MWh.

1-6) The carbon flow rate of the heat load depends on a heat load size and a carbon flow density of a heat load node. The heat load size may be obtained from a mass flow of the heat load node and supplied and returned water temperatures of the heat load node. The operation of determining the heat load carbon flow rate includes the following actions at 1-6-1), 1-6-2) and 1-6-3).

1-6-1) A heat load demand is determined as follows:

q _(j) =cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH)  (12),

where q_(j) represents a heat demand of a heat load j, unit: MW; Γ_(j) ^(NH) represents a node where the heat load j is located; and Ω^(LH) represents a set of heat loads.

1-6-2) Since there is no external energy injection at the heat load node, a node connected to the heat load have equal carbon flow densities in the water supply network and the water return network. A carbon flow density of a heat load node is determined as follows:

ρ_(n) ^(NHR)=ρ_(n) ^(NHS) ,n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH)  (13).

1-6-3) The heat load carbon flow rate may be determined as follows:

R _(j) ^(LH)=ρ_(n) ^(NHS) q _(j)=ρ_(n) ^(NHS) cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH)  (14),

where R_(j) ^(LH) represents a carbon flow rate of the heat load j, unit: tCO₂/h.

Optionally, in an embodiment of the present disclosure, the method for measuring the carbon emission of the district heating system further includes: calculating a matrix representation of the steady carbon emission flow model of the district heating system.

In an embodiment of the present disclosure, the operation of calculating the matrix representation of the steady carbon emission flow model of the district heating system includes: constructing a branch heat flow matrix, a branch network loss matrix, and a nodal heat flow flux matrix of the district heating system; and calculating a nodal carbon flow density vector of a heat network, and then calculating a branch carbon flow rate matrix, a network loss carbon flow rate matrix, and a load carbon flow rate vector of each of the water supply network and the water return network.

In some embodiments, an operation of constructing a matrix representation expression of the steady carbon emission flow model of the district heating system includes: constructing the branch heat flow matrix, the branch network loss matrix, and the nodal heat flow flux matrix of the district heating system. The operation of constructing the branch heat flow matrix, the branch network loss matrix, and the nodal heat flow flux matrix of the district heating system includes the following actions at 2-1), 2-2) and 2-3).

2-1) Elements of a branch energy flow matrix are related to a water flow and a temperature in a pipeline. The branch heat flow matrix of the district heating system is constructed. The branch heat flow matrix of the district heating system includes a branch heat flow matrix of the water supply network and a branch heat flow matrix of the water return network. The operation of constructing the branch heat flow matrix of the district heating system includes the following actions at 2-1-1) and 2-1-2).

2-1-1) Elements of the branch heat flow matrix of the water supply network are determined. Expressions of the elements are:

Q _(B,ij) ^(S) =cm _(k) ^(S) T _(k) ^(S,out) ,Q _(B,ji) ^(S)=0  (15),

where Q_(B,ij) ^(S) and Q_(B,ji) ^(S) represent elements in a branch heat flow matrix Q_(B) ^(S) of the water supply network.

2-1-2) Elements of the branch heat flow matrix of the water return network are determined. Expressions of the elements are:

Q _(B,ij) ^(R) =cm _(k) ^(R) T _(k) ^(R,out) ,Q _(B,ji) ^(R)=0  (16),

where Q_(B,ij) ^(R) and Q_(B,ji) ^(R) represent elements in a branch heat flow matrix Q_(B) ^(R) of the water return network.

2-2) Elements of the branch network loss matrix are related to a water flow and a temperature in a pipeline. The branch network loss matrix of the district heating system is constructed. The branch network loss matrix of the district heating system includes a branch network loss matrix of the water supply network and a branch network loss matrix of the water return network. The operation of constructing the branch network loss matrix of the district heating system includes the following actions at 2-2-1) and 2-2-2).

2-2-1) Elements of the branch network loss matrix of the water supply network are determined. Expressions of the elements are:

Q _(BL,ij) ^(S) =cm _(k) ^(S) T _(k) ^(S,Loss) ,Q _(BL,ji) ^(S)=0  (17),

where Q_(BL,ij) ^(S) and Q_(BL,ji) ^(S) represent elements in a branch network loss matrix Q_(BL) ^(S) of the water supply network.

2-2-2) Elements of the branch network loss matrix of the water return network are determined. Expressions of the elements are:

Q _(BL,ij) ^(R) =cm _(k) ^(R) T _(k) ^(R,Loss) ,Q _(BL,ji) ^(R)=0  (18),

where Q_(BL,ij) ^(R) and Q_(BL,ji) ^(R) represent elements in a branch network loss matrix Q_(BL) ^(R) of the water return network.

2-3) A nodal energy flow flux matrix of the heat network is related to a branch energy flow matrix and a heat source injection matrix. The nodal heat flow flux matrix of the district heating system is constructed. The nodal heat flow flux matrix of the district heating system includes a nodal heat flow flux matrix of the water supply network and a nodal heat flow flux matrix of the water return network. The operation of constructing the nodal heat flow flux matrix of the district heating system includes the following actions at 2-3-1), 2-3-2) and 2-3-3).

2-3-1) For a node in no connection to the heat source, an energy flow at the node is equal to a sum of energy flows of respective injection branches. The nodal heat flow flux matrix of the water supply network is determined. An expression of the nodal heat flow flux matrix of the water supply network is as follows:

Q _(N) ^(S)=diag{ζ_(N) _(NH) Q _(B) ^(S)}  (19),

where Q_(N) ^(S) represents the nodal heat flow flux matrix of the water supply network; ζ_(N) _(NH) represents a coefficient matrix of a branch heat flow; and N_(NH) represents a number of nodes of the district heating system.

2-3-2) For a node in no connection to the heat source, an energy flow at the node is equal to a sum of energy flows of respective injection branches. The nodal heat flow flux matrix of the water return network is determined. An expression of the nodal heat flow flux matrix of the water return network is as follows:

Q _(N) ^(R)=diag{ζ_(N) _(NH) Q _(B) ^(R)}  (20),

where Q_(N) ^(R) represents the nodal heat flow flux matrix of the water return network.

2-3-3) For a node connected to the heat source, an energy flow flowing through the node is also related to an injection of the heat source. A nodal integrated energy flow flux matrix is determined. An expression of the nodal integrated energy flow flux matrix is as follows:

{circumflex over (Q)} _(N) ^(S)=diag{ζ_(N) _(NH) Q _(B) ^(S)+ζ_(N) _(GH) Q _(G)}  (21),

where {circumflex over (Q)}_(N) ^(S) represents the nodal integrated energy flow flux matrix; ζ_(N) _(GH) represents a coefficient matrix of a heat flow injected by the heat source; and N_(GH) represents a number of heat sources of the district heating system.

2-4) For all nodes, a total injected carbon emission of the nodes is determined to be equal to a sum of injected carbon flow rates of all branches connected to the nodes. In some embodiments,

Q _(N) ^(S)ρ^(NHS)=(Q _(B) ^(S) +XQ _(BL) ^(S))^(T)ρ^(NHS)

Q _(N) ^(R)ρ^(NHR)=(Q _(B) ^(R) +XQ _(BL) ^(R))^(T)ρ^(NHR),  (22),

where ρ^(NHS) represents a matrix formed by the carbon flow density ρ_(n) ^(NHS) of the node n in the water supply network determined at the action of 1-3-3); and ρ^(NHR) represents a matrix formed by the carbon flow density ρ^(NHR) of the node n in the water return network determined at the action of 1-3-4).

2-4-1) For the heat load node, the heat load node is determined to have an equal carbon flow density in the water supply network and the water return network, an expression of which is as follows:

Bρ ^(NHS) =Bρ ^(NHR)  (23),

where B represents a heat load-node association matrix, when the heat load j is connected to the node n, B_(jn)=1, otherwise B_(jn)=0.

2-4-2) For the heat source node, a matrix relation of the heat source node is determined based on the conservation of carbon emission obtained at the action of 1-5-2) as:

C{circumflex over (Q)} _(N) ^(S)ρ^(NHS) =CQ _(N) ^(R)ρ^(NHR) +Q _(G) ^(T)ρ^(GH)  (24),

where C represents a 0-1 matrix associated with the heat source node, when the node n is connected to the heat source, C_(nn)=1, otherwise C_(nn)=0.

2-5) The action of 2-4) is rearranged to obtain a matrix expression as:

$\begin{matrix} {{\begin{bmatrix} {Q_{N}^{S} - \left( {Q_{B}^{S} + {XQ_{BL}^{S}}} \right)^{T}} & 0 \\ 0 & {Q_{N}^{R} - \left( {Q_{B}^{R} + {XQ}_{BL}^{R}} \right)^{T}} \\ B & {- B} \\ {C{\overset{\hat{}}{Q}}_{N}^{S}} & {{- C}Q_{N}^{R}} \end{bmatrix}\begin{bmatrix} \rho^{NHS} \\ \rho^{NHR} \end{bmatrix}} = {\begin{bmatrix} 0 \\ 0 \\ 0 \\ {Q_{G}^{T}\rho^{GH}} \end{bmatrix}.}} & (25) \end{matrix}$

Therefore, the nodal carbon flow density vector of the heat network may be obtained. An expression of the nodal carbon flow density vector of the heat network is:

$\begin{matrix} {\begin{bmatrix} \rho^{NHS} \\ \rho^{NHR} \end{bmatrix} = {{\begin{bmatrix} {Q_{N}^{S} - \left( {Q_{B}^{S} + {XQ_{BL}^{S}}} \right)^{T}} & 0 \\ 0 & {Q_{N}^{R} - \left( {Q_{B}^{R} + {XQ}_{BL}^{R}} \right)^{T}} \\ B & {- B} \\ {C{\overset{\hat{}}{Q}}_{N}^{S}} & {{- C}Q_{N}^{R}} \end{bmatrix}^{- 1}\begin{bmatrix} 0 \\ 0 \\ 0 \\ {Q_{G}^{T}\rho^{GH}} \end{bmatrix}}.}} & (26) \end{matrix}$

Therefore, after the nodal carbon flow density vector of the heat network is obtained, the branch carbon flow rate matrix, the network loss carbon flow rate matrix, and the load carbon flow rate vector of each of the water supply network and the water return network may be calculated.

At block S102, a dynamic carbon emission amount of the current district heating system is obtained using a pre-trained dynamic carbon emission flow model. The pre-trained dynamic carbon emission flow model is constructed based on water element carbon flow rates at a plurality of time periods, actual outlet carbon flow rates of a pipeline at the plurality of time periods, network loss carbon flow rates at the plurality of time periods, and nodal carbon flow densities at the plurality of time periods of the current district heating system.

Due to a conveying delay in the heat network, a water flow flowing out of a pipeline in the heat network at a time period is different from a water flow injecting into the pipeline at the time period, which leads to a difference between the inlet carbon flow rate and an inlet carbon flow density, and the outlet carbon flow rate and an outlet carbon flow density of the pipeline in the heat network. Cell characterization is used to describe characteristics of dynamic conveying of the district heating system. The water flow flowing out of the pipeline is actually a mixture of injected water flows at several previous time periods, which may be seen as a combination of several water element components. The dynamic carbon emission flow model of the district heating system is established, which includes the water element carbon flow rates at the plurality of time periods, the actual outlet carbon flow rates of the pipeline at the plurality of time periods, the network loss carbon flow rates at the plurality of time periods, and the nodal carbon flow densities at the plurality of time periods. The operation of establishing the dynamic carbon emission flow model of the district heating system includes the following actions at 3-1), 3-2), 3-3) and 3-4).

3-1) The water element is defined as a mass flow of water in a pipeline per unit time. According to the conservation of carbon emission, a carbon flow rate corresponding to mixed hot water may be similarly expressed as a linear combination of carbon flow rates corresponding to several water elements. An expression of the carbon flow rate corresponding to mixed hot water is:

$\begin{matrix} {{{\overset{\sim}{R}}_{k,t}^{{BHS},{out}} = {\frac{R_{k,{t - \delta_{k,t}}}^{{BHS},{in}}\left( {B_{k,t} - {\sigma M_{k}}} \right)}{\left( {m_{k,{t - \delta_{k,t}}}^{S}\Delta t} \right)} + {\sum\limits_{\tau = {t - \varphi_{k,t} + 1}}^{t - \delta_{k,t} - 1}R_{k,\tau}^{{BHS},{in}}} + \frac{R_{k,{t - \delta_{k,t}}}^{{BHS},{in}}\left( {{m_{k,t}^{S}\Delta t} + {\sigma M_{k}} - A_{k,t}} \right)}{\left( {m_{k,{t - \varphi_{k,t}}}^{S}\Delta t} \right)}}},} & (27) \end{matrix}$

where {tilde over (R)}_(k,t) ^(BHS,out) represents a water element carbon flow rate at a time period t; σ represents a density of water; M_(k) represents a volume of the pipeline k; φ_(k,t) represents an injection time period of an earliest water element component contained in a water flow flowing out of the pipeline k at the time period t; δ_(k,t) represents an injection time period of a latest water element component contained in the water flow flowing out of the pipeline k at the time period t, and is related to the conveying delay of the district heating system; A_(k,t) represents a total injection water flow amount for φ_(k,t) time periods before the time period t; B_(k,t) represents a total injection water flow amount from a time period t−δ_(k,t) to the time period t; and expressions for A_(k,t) and B_(k,t) are:

$\begin{matrix} {A_{k,t} = \left\{ {\begin{matrix} {{\sum\limits_{\tau = {t - \varphi_{k,t} + 1}}^{t}{m_{k,\tau}^{S}\Delta t}},} & {\varphi_{k,t} \geq {\delta_{k,t} + 1}} \\ {B_{k,t},} & {\varphi_{k,t} < {\delta_{k,t} + 1}} \end{matrix},} \right.} & (28) \end{matrix}$ $\begin{matrix} {B_{k,t} = {\sum\limits_{\tau = {t - \delta_{k,t}}}^{t}{m_{k,\tau}^{S}\Delta{t.}}}} & (29) \end{matrix}$

and

3-2) The actual outlet carbon flow rates of the pipeline at the plurality of time periods and the network loss carbon flow rates at the plurality of time periods are determined. The operation of determining the actual outlet carbon flow rates of the pipeline at the plurality of time periods and the network loss carbon flow rates at the plurality of time periods includes the following actions at 3-2-1), 3-2-2) and 3-2-3).

3-2-1) An actual temperature of an outlet water flow of the pipeline may be obtained by taking a conveying loss of the pipeline into consideration. An expression of the actual temperature of the outlet water flow of the pipeline is as follows:

$\begin{matrix} {{T_{k,t}^{S,{out}} = {{\overset{˜}{T}}_{k,t}^{S,{out}}{\exp\left( {- \frac{\lambda L_{k}}{cm_{k,t}^{S}}} \right)}}},} & (30) \end{matrix}$

where T_(k,t) ^(S,out) represents the actual temperature of the outlet water flow of the pipeline; {tilde over (T)}_(k,t) ^(S,out) represents a weighted average of temperatures of injection water flows at previous time periods; λ represents a thermal conductivity coefficient of the pipeline; and L_(k) represents a length of the pipeline k.

3-2-2) The carbon flow density remains constant in a process in which only a temperature of a water flow decreases along a pipeline, without any mixing or an outflow of the water flow. An expression of an actual outlet carbon flow rate of the pipeline at the time period t is as follows:

$\begin{matrix} {R_{k,t}^{{BHS},{out}} = {{\overset{\sim}{R}}_{k,t}^{{BHS},{out}}{\frac{T_{k,t}^{S,{out}}}{{\overset{\sim}{T}}_{k,t}^{S,{out}}}.}}} & (31) \end{matrix}$

3-2-3) A network loss carbon flow rate of the pipeline at the time period t is determined. An expression of the network loss carbon flow rate of the pipeline at the time period t is as follows:

$\begin{matrix} {R_{k,t}^{{BHS},{loss}} = {{{\overset{\sim}{R}}_{k,t}^{{BHS},{loss}}\left( {1 - \frac{T_{k,t}^{S,{out}}}{{\overset{\sim}{T}}_{k,t}^{S,{out}}}} \right)}.}} & (32) \end{matrix}$

3-3) The nodal carbon flow densities at the plurality of time periods are determined based on the action of 1-3-2) and the action of 1-3-3). An expression of the nodal carbon flow densities at the plurality of time periods is:

$\begin{matrix} {\rho_{n,t}^{NHS} = {\frac{\sum\limits_{k \in \Omega_{n}^{{BH} +}}\left( {R_{k,t}^{{BHS},{out}} + {XR_{k,t}^{{BHS},{Loss}}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{cm_{k,t}^{S}T_{k,t}^{S,{out}}}}.}} & (33) \end{matrix}$

3-4) The nodal carbon flow densities at the plurality of time periods are determined for the water return network. An expression of the nodal carbon flow densities at the plurality of time periods is:

$\begin{matrix} {\rho_{n,t}^{NHR} = {\frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}\left( {R_{k,t}^{{BHR},{out}} + {XR_{k,t}^{{BHR},{Loss}}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{cm_{k,t}^{R}T_{k,t}^{R,{out}}}}.}} & (34) \end{matrix}$

At block S103, a carbon emission amount of the current district heating system is counted based on the steady carbon emission amount and the dynamic carbon emission amount.

As illustrated in FIG. 2 , a framework structure of a method for measuring carbon emission of a district heating system according to an embodiment of the present disclosure is displayed. Based on the steady carbon emission flow model and the dynamic carbon emission flow model that are constructed by the method illustrated in FIG. 2 , steady and dynamic carbon emission indicators of the current district heating system are obtained.

In an embodiment of the present disclosure, a network structure and a calculation result of a steady carbon emission flow of a 6-node district heating system are as illustrated in FIG. 3 . A heat load size of node 5 and node 6 are 120 MW and 100 MW, respectively. According to the calculation result of the steady carbon emission flow, carbon flow densities of two heat sources HS1 and HS2 are 0.222 tCO₂/MWh and 0.267 tCO₂/MWh, respectively. A total carbon flow rate of an injection of the heat source, a total carbon flow rate of the heat load, and a total carbon flow rate due to a network loss are 68.63 tCO₂/h, 53.14 tCO₂/h, and 15.49 tCO₂/h, respectively.

According to the dynamic carbon emission flow model of the district heating system provided in the present disclosure, carbon flow densities of each node in the water supply network of the district heating system at different time periods are calculated and illustrated in FIG. 4 .

With the method for measuring the carbon emission of the district heating system according to the embodiments of the present disclosure, the steady carbon emission flow model of the district heating system is established based on the carbon emission flow theory, and a corresponding matrix calculation expression is provided. The dynamic carbon emission flow model of the district heating system is established with a conveying delay in a heat flow taken into consideration. The steady and dynamic carbon emission indicators of the district heating system are obtained. In this way, carbon emission details of each link of a source, a grid, and a load of the district heating system can be effectively identified, carbon emission responsibilities on both a source side and a load side can be clarified, and accurate measurement of the carbon emission of the district heating system can be realized. In addition, with the help of a data collection, processing, and display system, a calculation result of a carbon meter system can be displayed intuitively to heat users, which can guide the heat users to reduce the carbon emission interactively, and have high application value.

An apparatus for measuring carbon emission of a district heating system according to an embodiment of the present disclosure is described below with reference to the accompanying drawings.

FIG. 5 is an example diagram of an apparatus for measuring carbon emission of a district heating system according to an embodiment of the present disclosure.

As illustrated in FIG. 5 , the apparatus for measuring the carbon emission of the district heating system includes a plurality of heat source-side carbon meters, a plurality of heat pipeline carbon meters, a plurality of user-side carbon meters, and a central server.

Each of the plurality of heat source-side carbon meters is connected to a heat source and configured to measure heat source-side carbon emission.

Each of the plurality of heat pipeline carbon meters is connected to a heat pipeline and the heat source-side carbon meter. The heat pipeline carbon emission meter is configured to measure heat pipeline carbon emission.

Each of the plurality of user-side carbon meters has one end connected to a heat user end and another end connected to the heat pipeline carbon meter, and is configured to obtain a carbon potential of a node where a user is located and obtain a carbon emission amount resulted from heat consumption of the user.

As a calculation center, the central server is responsible for calculation of the carbon emission flow of the district heating system, and for communicating with the carbon meter disposed in each link to obtain carbon emission of each link. The central server is connected to the plurality of heat source-side carbon meters and the plurality of heat pipeline carbon meters, and configured to calculate a carbon emission intensity of the heat source based on coal consumption data of the heat source and an emission coefficient of the coal, calculate a distribution of a carbon emission flow in the heat pipeline, and calculate a carbon emission amount corresponding to a pipeline connected to the node based on data of the heat pipeline carbon meter.

Optionally, in an embodiment of the present disclosure, each of the heat source-side carbon meter, the heat pipeline carbon meter, and the user-side carbon meter is further configured to display in real time a result of the carbon emission of the district heating system calculated by the central server.

In the embodiments of the present disclosure, each of the heat source-side carbon meter, the heat pipeline carbon meter, and the user-side carbon meter is configured to collect and calculate information needed for measuring the carbon emission, and transmit relevant information to the central server. The central server is configured to calculate the carbon emission of the district heating system using the collected information, and feed a calculation result back to each carbon meter. The carbon meter is configured to display the calculation result fed back by the central server in real time.

In the embodiments of the present disclosure, the plurality of carbon meters forms a carbon meter system. The carbon meter system is a hierarchical system divided into an upper level and a lower level. The upper level of the carbon meter system includes the central server, the heat source-side carbon meter, and the heat pipeline carbon meter, and is configured to calculate the carbon emission intensity of the heat source based on the coal consumption data of the heat source and the emission coefficient of the coal, and then calculate the distribution of the carbon emission flow in the heat pipeline; and calculate the carbon emission amount corresponding to the pipeline connected to the node based on the data of the heat pipeline carbon meter. The lower level of the carbon meter system consists of user-side carbon meters. The user-side carbon meter is configured to communicate with the heat pipeline carbon meter to obtain the carbon potential of the node where the user is located and obtain the carbon emission amount resulted from the heat consumption of the user.

It should be noted that the above explanatory description of the embodiments of the method for measuring the carbon emission of the district heating system is also applicable to the apparatus for measuring the carbon emission of the district heating system, and details thereof will be omitted here.

The apparatus for measuring the carbon emission of the district heating system according to the embodiments of the present disclosure is formed by carbon meters scattered in various links of the district heating system for measuring the carbon emission, the central server, and a communication line. In some embodiments, the carbon meters scattered in various links of the district heating system include the heat source-side carbon meter, a pipeline-side carbon meter, and a heat-user side carbon meter. In this way, the carbon emission details of each link of the source, the grid, and the load of the district heating system can be effectively identified, the carbon emission responsibilities on both the source side and the load side can be clarified, and the accurate measurement of the carbon emission of the district heating system can be realized, which has high application value.

FIG. 6 is a schematic diagram showing a structure of an electronic device according to an embodiment of the present disclosure. The electronic device may include a memory 601, a processor 602, and a computer program stored in the memory 601 and executable on the processor 602. The processor 602, when executing the computer program, implements the method for measuring the carbon emission of the district heating system according to any of the above embodiments.

Further, the electronic device includes: a communication interface 603 configured for communication between the memory 601 and the processor 602; and the memory 601 stores a computer program executable on the processor 602. The memory 601 may include a high-speed Random Access Memory (RAM), or may also include a non-volatile memory, such as at least one disk memory.

When the memory 601, the processor 602, and the communication interface 603 are implemented independently, the communication interface 603, the memory 601, and the processor 602 may be interconnected and communicate with each other via a bus. The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The buses may be divided into an address bus, a data bus, a control bus, etc. For the convenience of description, only one thick line is used in FIG. 6 , but it does not mean that there is only one bus or one type of bus.

Optionally, in a specific implementation, when the memory 601, the processor 602, and the communication interface 603 are integrated on a single chip for an implementation, the memory 601, the processor 602, and the communication interface 603 may communicate with each other through an internal interface.

The processor 602 may be a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement an embodiment of the present disclosure.

A computer-readable storage medium is further provided according to an embodiment. The computer-readable storage medium stores a computer program. The computer program, when executed by a processor, implements the method for measuring the carbon emission of the district heating system as described above.

In the description of this specification, descriptions with reference to the terms “an embodiment”, “some embodiments”, “examples”, “specific examples”, or “some examples” etc., mean that specific features, structure, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine the different embodiments or examples and the features of the different embodiments or examples described in this specification without contradicting each other.

In addition, the terms “first” and “second” are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with “first” and “second” may explicitly or implicitly include at least one of the features. In the description of the present disclosure, “N” means at least two, such as two, three, etc., unless otherwise specifically defined.

Any process or method described in a flowchart or described herein in other ways may be understood to include one or N modules, segments, or portions of codes of executable instructions for achieving specific logical functions or steps in the process. The scope of a preferred embodiment of the present disclosure includes other implementations, in which a function may be performed not in a sequence shown or discussed, including a substantially simultaneous manner or a reverse sequence based on the function involved, which should be understood by those skilled in the art to which the embodiments of the present disclosure belong.

It should be understood that each part of the present disclosure may be realized by hardware, software, firmware, or a combination thereof. In the above embodiments, N steps or methods may be realized by software or firmware stored in the memory and executed by an appropriate instruction execution system. For example, when it is realized by the hardware, likewise in another embodiment, the steps or methods may be realized by one or a combination of the following techniques known in the art: a discrete logic circuit having a logic gate circuit for realizing a logic function of a data signal, an application-specific integrated circuit having an appropriate combination logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), etc.

It should be understood by those skilled in the art that all or a part of the steps carried by the method in the above-described embodiments may be completed by relevant hardware instructed by a program. The program may be stored in a computer-readable storage medium. When the program is executed, one or a combination of the steps of the method in the above-described embodiments may be included. 

What is claimed is:
 1. A method for measuring carbon emission of a district heating system, the method comprising: obtaining a steady carbon emission amount of a current district heating system using a pre-trained steady carbon emission flow model, wherein the pre-trained steady carbon emission flow model is constructed based on a pipeline carbon flow rate, network loss carbon emission, a nodal carbon flow density, a pipeline carbon flow density, a heat source carbon flow rate, and a heat load carbon flow rate of the current district heating system; obtaining a dynamic carbon emission amount of the current district heating system using a pre-trained dynamic carbon emission flow model, wherein the pre-trained dynamic carbon emission flow model is constructed based on water element carbon flow rates at a plurality of time periods, actual outlet carbon flow rates of a pipeline at the plurality of time periods, network loss carbon flow rates at the plurality of time periods, and nodal carbon flow densities at the plurality of time periods of the current district heating system; and counting a carbon emission amount of the current district heating system based on the steady carbon emission amount and the dynamic carbon emission amount.
 2. The method according to claim 1, further comprising: constructing the steady carbon emission flow model of the district heating system based on the pipeline carbon flow rate, the network loss carbon emission, the nodal carbon flow density, the pipeline carbon flow density, the heat source carbon flow rate, and the heat load carbon flow rate of the district heating system, wherein said constructing the steady carbon emission flow model of the district heating system based on the pipeline carbon flow rate, the network loss carbon emission, the nodal carbon flow density, the pipeline carbon flow density, the heat source carbon flow rate, and the heat load carbon flow rate of the district heating system is: determining the pipeline carbon flow rate of the district heating system comprising a carbon flow rate of a water supply network and a carbon flow rate of a water return network, the carbon flow rate of the water supply network being: R _(k) ^(BHS,in)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,in) ,∀k∈Ω ^(BH) R _(k) ^(BHS,out)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,out) ,∀k∈Ω ^(BH), where R_(k) ^(BHS,in) and R_(k) ^(BHS,out) represent an inlet carbon flow rate and an outlet carbon flow rate of a pipeline k in the water supply network, respectively, unit: tCO₂/h; ρ_(k) ^(BHS) represents a carbon flow density of the pipeline k in the water supply network, unit: tCO₂/MWh; c represents a specific heat capacity of water, unit: MWh/(kg·° C.); m_(k) ^(S) represents a mass flow of the pipeline k in the water supply network, unit: kg/h; T_(k) ^(S,in) and T_(k) ^(S,out) represent an inlet temperature and an outlet temperature of the pipeline k in the water supply network, unit: ° C.; and Ω^(BH) represents a set of pipelines in the district heating system; and the carbon flow rate of the water return network being: R _(k) ^(BHR,in)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,in) ,∀k∈Ω ^(BH) R _(k) ^(BHR,out)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,out) ,∀k∈Ω ^(BH), where R_(k) ^(BHR,in) and R_(k) ^(BHR,out) represent an inlet carbon flow rate and an outlet carbon flow rate of a pipeline k in the water return network, respectively, unit: tCO₂/h; ρ_(k) ^(BHR) represents a carbon flow density of the pipeline k in the water return network, unit: tCO₂/h; m_(k) ^(R) represents a mass flow of the pipeline k in the water return network, unit: kg/h; and T_(k) ^(R,in) and T_(k) ^(R,out) represent an inlet temperature and an outlet temperature of the pipeline k in the water return network, unit: ° C.; determining the network loss carbon emission of the district heating system comprising a network loss carbon flow rate of the water supply network and a network loss carbon flow rate of the water return network, said determining the network loss carbon emission of the district heating system being: determining a temperature difference of a pipeline in the water supply network and a temperature difference of a pipeline in the water return network: T _(k) ^(S,Loss) =T _(k) ^(S,in) −T _(k) ^(S,out) T _(k) ^(R,Loss) =T _(k) ^(R,in) −T _(k) ^(R,out), where T_(k) ^(S,Loss) and T_(k) ^(R,Loss) represent a temperature difference between both ends of the pipeline k in the water supply network and a temperature difference between both ends of the pipeline k in the water return network, respectively, unit: ° C.; and determining the network loss carbon flow rate of the water supply network and the network loss carbon flow rate of the water return network: R _(k) ^(BHS,Loss)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,Loss) ,∀k∈Ω ^(BH) R _(k) ^(BHR,Loss)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,Loss) ,∀k∈Ω ^(BH), where R_(k) ^(BHS,Loss) and R_(k) ^(BHR,Loss) represent a network loss carbon flow rate of the pipeline k in the water supply network and a network loss carbon flow rate of the pipeline k in the water return network, respectively, unit: tCO₂/h; determining the nodal carbon flow density of the district heating system, said determining the nodal carbon flow density of the district heating system comprising: determining, for each node in the district heating system, that conservation of mass and conservation of energy are satisfied at the node: ${m_{n}^{S} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}m_{k}^{S}}},{\forall{n \in \Omega^{NH}}}$ ${{T_{n}^{S}m_{n}^{S}} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}{T_{k}^{S,{out}}m_{k}^{S}}}},{\forall{n \in \Omega^{NH}}},$ where m_(n) ^(S) represents a total mass flow flowing through a node n in the water supply network, unit: kg/h; Ω_(n) ^(BH+) represents a set of injection pipelines at the node n in the water supply network; Ω^(NH) represents a set of nodes in the district heating system; and T_(n) ^(S) represents a water flow temperature of the node n in the water supply network, unit: ° C.; determining, for each node in the district heating system, that conservation of carbon emission is satisfied at the node, a carbon flow rate of the node n being equal to a sum of outlet carbon flow rates of all the injection pipelines and network loss carbon flow rates allocated to the injection pipelines; ${R_{n}^{NHS} = {{\sum\limits_{k \in \Omega_{n}^{{BH} +}}\left( {R_{k}^{{BHS},{out}} + {XR}_{k}^{{BHS},{Loss}}} \right)} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}{\rho_{k}^{BHS}c{m_{k}^{S}\left( {T_{k}^{S,{out}} + {XT_{k}^{S,{Loss}}}} \right)}}}}},{\forall{n \in \Omega^{NH}}},$ where R_(n) ^(NHS) represents the carbon flow rate of the node n in the water supply network, unit: tCO₂/h; and X represents an allocating coefficient of a network loss carbon flow rate of an injection pipeline; determining a carbon flow density of the node n in the water supply network: ${\rho_{n}^{NHS} = {\frac{R_{n}^{NHS}}{cm_{n}^{S}T_{n}^{S}} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{\rho_{k}^{BHS}{m_{k}^{S}\left( {T_{k}^{S,{out}} + {XT_{k}^{S,{Loss}}}} \right)}}}{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{m_{k}^{S}T_{k}^{S,{out}}}}}},{\forall{n \in \Omega^{NH}}},$ where ρ_(n) ^(NHS) represents the carbon flow density of the node n in the water supply network, unit: tCO₂/MWh; and determining a carbon flow density of the node n in the water return network: ${\rho_{n}^{NHR} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{\rho_{k}^{BHR}{m_{k}^{R}\left( {T_{k}^{R,{out}} + {XT}_{k}^{R,{Loss}}} \right)}}}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{m_{k}^{R}T_{k}^{R,{out}}}}},{\forall{n \in \Omega^{NH}}},$ where ρ_(n) ^(NHR) represents the carbon flow density of the node n in the water return network, unit: tCO₂/MWh; and Ω_(n) ^(BH−) represents a set of outflow pipelines at the node n in the water supply network; determining the pipeline carbon flow density of the district heating system: ρ_(k) ^(BHS)=ρ_(n) ^(NHS) ,n=Γ _(k) ^(NH+) ,∀k∈Ω ^(BH) ρ_(k) ^(BHR)=ρ_(n) ^(NHR) ,n=Γ _(k) ^(NH−) ,∀k∈Ω ^(BH), where Γ_(k) ^(NH+) and Γ_(k) ^(NH+) represent an injection node and an outflow node of the pipeline k in the water supply network, respectively; determining the heat source carbon flow rate of the district heating system, said determining the heat source carbon flow rate of the district heating system comprising: determining a heat output of a heat source: Q _(i) =cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(i) ^(NH) ,∀i∈Ω ^(GH), where Q_(i) represents a heat output of a heat source i, unit: MW; Γ_(i) ^(NH) represents a node where the heat source i is located; and Ω^(GH) represents a set of heat sources; and determining that conservation of carbon emission at a heat source node is satisfied: ρ_(n) ^(NHS) cm _(n) ^(S) T _(n) ^(S)=ρ_(i) ^(GH) Q _(i)+ρ_(n) ^(NHR) cm _(k) ^(S) T _(k) ^(R) ,n=Γ _(i) ^(NH) ,∀i∈Ω ^(GH), where ρ_(i) ^(GH) represents a carbon flow density of the heat source i, unit: tCO₂/MWh; and determining the heat load carbon flow rate of the district heating system, said determining the heat load carbon flow rate of the district heating system comprising: determining a heat load demand: q _(j) =cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH), where q_(j) represents a heat demand of a heat load j, unit: MW; Γ_(j) ^(NH) represents a node where the heat load j is located; and Ω^(LH) represents a set of heat loads; determining a carbon flow density of a heat load node: ρ_(n) ^(NHR)=ρ_(n) ^(NHS) ,n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH); and determining the heat load carbon flow rate: R _(j) ^(LH)=ρ_(n) ^(NHS) q _(j)=ρ_(n) ^(NHS) cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH), where R_(j) ^(LH) represents a carbon flow rate of the heat load j, unit: tCO₂/h.
 3. The method according to claim 2, further comprising: calculating a matrix representation of the steady carbon emission flow model of the district heating system.
 4. The method according to claim 3, wherein said calculating the matrix representation of the steady carbon emission flow model of the district heating system comprises: constructing a branch heat flow matrix, a branch network loss matrix, and a nodal heat flow flux matrix of the district heating system; and calculating a nodal carbon flow density vector of a heat network, and then calculating a branch carbon flow rate matrix, a network loss carbon flow rate matrix, and a load carbon flow rate vector of each of the water supply network and the water return network.
 5. The method according to claim 4, wherein said calculating the matrix representation of the steady carbon emission flow model of the district heating system comprises: constructing the branch heat flow matrix of the district heating system comprising a branch heat flow matrix of the water supply network and a branch heat flow matrix of the water return network, wherein said constructing the branch heat flow matrix of the district heating system comprises: determining elements of the branch heat flow matrix of the water supply network: Q _(B,ij) ^(S) =cm _(k) ^(S) T _(k) ^(S,out) ,Q _(B,ji) ^(S)=0, where Q_(B,ij) ^(S) and Q_(B,ji) ^(S) represent elements in a branch heat flow matrix Q_(B) ^(S) of the water supply network; and determining elements of the branch heat flow matrix of the water return network: Q _(B,ij) ^(R) =cm _(k) ^(R) T _(k) ^(R,out) ,Q _(B,ji) ^(R)=0, where Q_(B,ij) ^(R) and Q_(B,ji) ^(R) represent elements in a branch heat flow matrix Q_(B) ^(R) of the water return network; constructing the branch network loss matrix of the district heating system comprising a branch network loss matrix of the water supply network and a branch network loss matrix of the water return network, wherein said constructing the branch network loss matrix of the district heating system comprises: determining elements of the branch network loss matrix of the water supply network: Q _(BL,ij) ^(S) =cm _(k) ^(S) T _(k) ^(S,Loss) ,Q _(BL,ji) ^(S)=0 where Q_(BL,ij) ^(S) and Q_(BL,ji) ^(S) represent elements in a branch network loss matrix Q_(BL) ^(S) of the water supply network; and determining elements of the branch network loss matrix of the water return network: Q _(BL,ij) ^(R) =cm _(k) ^(R) T _(k) ^(R,Loss) ,Q _(BL,ji) ^(R)=0, where Q_(BL,ij) ^(R) and Q_(BL,ji) ^(R) represent elements in a branch network loss matrix Q_(BL) ^(R) of the water return network; constructing the nodal heat flow flux matrix of the district heating system comprising a nodal heat flow flux matrix of the water supply network and a nodal heat flow flux matrix of the water return network, wherein said constructing the nodal heat flow flux matrix of the district heating system comprises: determining, for a node in no connection to the heat source, the nodal heat flow flux matrix of the water supply network: Q _(N) ^(S)=diag{ζ_(N) _(NH) Q _(B) ^(S)}, where Q_(N) ^(S) represents the nodal heat flow flux matrix of the water supply network; ζ_(N) _(NH) represents a coefficient matrix of a branch heat flow; and N_(NH) represents a number of nodes of the district heating system; determining, for a node in no connection to the heat source, the nodal heat flow flux matrix of the water return network: Q _(N) ^(R)=diag{ζ_(N) _(NH) Q _(B) ^(R)}, where Q_(N) ^(R) represents the nodal heat flow flux matrix of the water return network; determining, for a node connected to the heat source, a nodal integrated energy flow flux matrix: {circumflex over (Q)} _(N) ^(S)=diag{ζ_(N) _(NH) Q _(B) ^(S)+ζ_(N) _(GH) Q _(G)}, where {circumflex over (Q)}_(N) ^(S) represents the nodal integrated energy flow flux matrix; ζ_(N) _(GH) represents a coefficient matrix of a heat flow injected by the heat source; and N_(GH) represents a number of heat sources of the district heating system; determining, for all nodes, that a total injected carbon emission of the nodes is equal to a sum of injected carbon flow rates of all branches connected to the nodes: Q _(N) ^(S)ρ^(NHS)=(Q _(B) ^(S) +XQ _(BL) ^(S))^(T)ρ^(NHS) Q _(N) ^(R)ρ^(NHR)=(Q _(B) ^(R) +XQ _(BL) ^(R))^(T)ρ^(NHR), where ρ^(NHS) represents a matrix formed by the carbon flow density ρ_(n) ^(NHS) of the node n in the water supply network; and ρ^(NHR) represents a matrix formed by the carbon flow density ρ_(n) ^(NHR) of the node n in the water return network; determining, for the heat load node, that the heat load node has an equal carbon flow density in the water supply network and the water return network: Bρ ^(NHS) =Bρ ^(NHR), where B represents a heat load-node association matrix, when the heat load j is connected to the node n, B_(jn)=1, otherwise B_(jn)=0; determining, for the heat source node, a matrix relation of the heat source node based on a conservation of carbon emission as: C{circumflex over (Q)} _(N) ^(S)ρ^(NHS) =CQ _(N) ^(R)ρ^(NHR) +Q _(G) ^(T)ρ^(GH), where C represents a 0-1 matrix associated with the heat source node, when the node n is connected to the heat source, C_(nn)=1, otherwise C_(nn)=0; determining the nodal carbon flow density vector of the heat network as: ${\begin{bmatrix} \rho^{NHS} \\ \rho^{NHR} \end{bmatrix} = {\begin{bmatrix} {Q_{N}^{S} - \left( {Q_{B}^{S} + {XQ_{BL}^{S}}} \right)^{T}} & 0 \\ 0 & {Q_{N}^{R} - \left( {Q_{B}^{R} + {XQ}_{BL}^{R}} \right)^{T}} \\ B & {- B} \\ {C{\overset{\hat{}}{Q}}_{N}^{S}} & {{- C}Q_{N}^{R}} \end{bmatrix}^{- 1}\begin{bmatrix} 0 \\ 0 \\ 0 \\ {Q_{G}^{T}\rho^{GH}} \end{bmatrix}}};$ and calculating the branch carbon flow rate matrix, the network loss carbon flow rate matrix, and the load carbon flow rate vector of each of the water supply network and the water return network.
 6. The method according to claim 5, further comprising: constructing the dynamic carbon emission flow model of the district heating system based on the water element carbon flow rates at the plurality of time periods, the actual outlet carbon flow rates of the pipeline at the plurality of time periods, the network loss carbon flow rates at the plurality of time periods, and the nodal carbon flow densities at the plurality of time periods, wherein said constructing the dynamic carbon emission flow model of the district heating system based on the water element carbon flow rates at the plurality of time periods, the actual outlet carbon flow rates of the pipeline at the plurality of time periods, the network loss carbon flow rates at the plurality of time periods, and the nodal carbon flow densities at the plurality of time periods is: determining the water element carbon flow rates at the plurality of time periods: ${{\overset{\sim}{R}}_{k,t}^{{BHS},{out}} = {\frac{R_{k,{t - \delta_{k,t}}}^{{BHS},{in}}\left( {B_{k,t} - {\sigma M_{k}}} \right)}{\left( {m_{k,{t - \delta_{k,t}}}^{S}\Delta t} \right)} + {\sum\limits_{\tau = {t - \varphi_{k,t} + 1}}^{t - \delta_{k,t} - 1}R_{k,\tau}^{{BHS},{in}}} + \frac{R_{k,{t - \delta_{k,t}}}^{{BHS},{in}}\left( {{m_{k,t}^{S}\Delta t} + {\sigma M_{k}} - A_{k,t}} \right)}{\left( {m_{k,{t - \varphi_{k,t}}}^{S}\Delta t} \right)}}},$ where {tilde over (R)}_(k,t) ^(BHS,out) represents a water element carbon flow rate at a time period t; σ represents a density of water; M_(k) represents a volume of the pipeline k; φ_(k,t) represents an injection time period of an earliest water element component contained in a water flow flowing out of the pipeline k at the time period t; δ_(k,t) represents an injection time period of a latest water element component contained in the water flow flowing out of the pipeline k at the time period t; A_(k,t) represents a total injection water flow amount for φ_(k,t) time periods before the time period t; B_(k,t) represents a total injection water flow amount from a time period t−δ_(k,t) to the time period t; and expressions for A_(k,t) and B_(k,t) are: $A_{k,t} = \left\{ {\begin{matrix} {{\sum\limits_{\tau = {t - \varphi_{k,t} + 1}}^{t}{m_{k,\tau}^{S}\Delta t}},} & {\varphi_{k,t} \geq {\delta_{k,t} + 1}} \\ {B_{k,t},} & {\varphi_{k,t} < {\delta_{k,t} + 1}} \end{matrix},} \right.$ ${B_{k,t} = {\sum\limits_{\tau = {t - \delta_{k,t}}}^{t}{m_{k,\tau}^{S}\Delta t}}};$ and determining the actual outlet carbon flow rates of the pipeline at the plurality of time periods and the network loss carbon flow rates at the plurality of time periods, said determining the actual outlet carbon flow rates of the pipeline at the plurality of time periods and the network loss carbon flow rates at the plurality of time periods comprising: calculating an actual temperature of an outlet water flow of the pipeline based on a conveying loss of the pipeline: ${T_{k,t}^{S,{out}} = {{\overset{˜}{T}}_{k,t}^{S,{out}}\exp\left( {- \frac{\lambda L_{k}}{{cm}_{k,t}^{S}}} \right)}},$ where T_(k,t) ^(S,out) represents the actual temperature of the outlet water flow of the pipeline; {tilde over (T)}_(k,t) ^(S,out) represents a weighted average of temperatures of injection water flows at previous time periods; λ represents a thermal conductivity coefficient of the pipeline; and L_(k) represents a length of the pipeline k; determining an actual outlet carbon flow rate of the pipeline at the time period t: R k , t BHS , out = R ~ k , t BHS , out ⁢ T k , t S , out T ~ k , t S , o ⁢u ⁢ t ; and determining a network loss carbon flow rate of the pipeline at the time period t: ${R_{k,t}^{{BHS},{Loss}} = {{\overset{˜}{R}}_{k,t}^{{BHS},{Loss}}\left( {1 - \frac{T_{k,t}^{S,{out}}}{{\overset{\sim}{T}}_{k,t}^{S,{out}}}} \right)}};$ determining the nodal carbon flow densities at the plurality of time periods: ${\rho_{n,t}^{NHS} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} +}}\left( {R_{k,t}^{{BHS},{out}} + {XR_{k,t}^{{BHS},{Loss}}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{cm_{k,t}^{S}T_{k,t}^{S,{out}}}}};$ and determining, for the water return network, the nodal carbon flow densities at the plurality of time periods: $\rho_{n,t}^{NHR} = {\frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}\left( {R_{k,t}^{{BHR},{out}} + {XR_{k,t}^{{BHR},{Loss}}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{cm_{k,t}^{R}T_{k,t}^{R,{out}}}}.}$
 7. An apparatus for measuring carbon emission of a district heating system, the apparatus comprising: a plurality of heat source-side carbon meters, wherein each of the plurality of heat source-side carbon meters is connected to a heat source and configured to measure heat source-side carbon emission; a plurality of heat pipeline carbon meters, wherein each of the plurality of heat pipeline carbon meters is connected to a heat pipeline and the heat source-side carbon meter, and the heat pipeline carbon emission meter is configured to measure heat pipeline carbon emission; a plurality of user-side carbon meters, wherein each of the plurality of user-side carbon meters has one end connected to a heat user end and another end connected to the heat pipeline carbon meter, and is configured to obtain a carbon potential of a node where a user is located and obtain a carbon emission amount resulted from heat consumption of the user; and a central server, wherein the central server is connected to the plurality of heat source-side carbon meters and the plurality of heat pipeline carbon meters, and configured to calculate a carbon emission intensity of the heat source based on coal consumption data of the heat source and an emission coefficient of the coal, calculate a distribution of a carbon emission flow in the heat pipeline, and calculate a carbon emission amount corresponding to a pipeline connected to the node based on data of the heat pipeline carbon meter.
 8. The apparatus according to claim 7, wherein each of the heat source-side carbon meter, the heat pipeline carbon meter, and the user-side carbon meter is further configured to display in real time a result of the carbon emission of the district heating system calculated by the central server.
 9. An electronic device, comprising: a memory; a processor; and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements: obtaining a steady carbon emission amount of a current district heating system using a pre-trained steady carbon emission flow model, wherein the pre-trained steady carbon emission flow model is constructed based on a pipeline carbon flow rate, network loss carbon emission, a nodal carbon flow density, a pipeline carbon flow density, a heat source carbon flow rate, and a heat load carbon flow rate of the current district heating system; obtaining a dynamic carbon emission amount of the current district heating system using a pre-trained dynamic carbon emission flow model, wherein the pre-trained dynamic carbon emission flow model is constructed based on water element carbon flow rates at a plurality of time periods, actual outlet carbon flow rates of a pipeline at the plurality of time periods, network loss carbon flow rates at the plurality of time periods, and nodal carbon flow densities at the plurality of time periods of the current district heating system; and counting a carbon emission amount of the current district heating system based on the steady carbon emission amount and the dynamic carbon emission amount.
 10. The electronic device according to claim 9, further comprising: constructing the steady carbon emission flow model of the district heating system based on the pipeline carbon flow rate, the network loss carbon emission, the nodal carbon flow density, the pipeline carbon flow density, the heat source carbon flow rate, and the heat load carbon flow rate of the district heating system, wherein said constructing the steady carbon emission flow model of the district heating system based on the pipeline carbon flow rate, the network loss carbon emission, the nodal carbon flow density, the pipeline carbon flow density, the heat source carbon flow rate, and the heat load carbon flow rate of the district heating system is: determining the pipeline carbon flow rate of the district heating system comprising a carbon flow rate of a water supply network and a carbon flow rate of a water return network, the carbon flow rate of the water supply network being: R _(k) ^(BHS,in)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,in) ,∀k∈Ω ^(BH) R _(k) ^(BHS,out)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,out) ,∀k∈Ω ^(BH), where R_(k) ^(BHS,in) and R_(k) ^(BHS,out) represent an inlet carbon flow rate and an outlet carbon flow rate of a pipeline k in the water supply network, respectively, unit: tCO₂/h; ρ_(k) ^(BHS) represents a carbon flow density of the pipeline k in the water supply network, unit: tCO₂/MWh; c represents a specific heat capacity of water, unit: MWh/(kg·° C.); m_(k) ^(S) represents a mass flow of the pipeline k in the water supply network, unit: kg/h; T_(k) ^(S,in) and T_(k) ^(S,out) represent an inlet temperature and an outlet temperature of the pipeline k in the water supply network, unit: ° C.; and Ω^(BH) represents a set of pipelines in the district heating system; and the carbon flow rate of the water return network being: R _(k) ^(BHR,in)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,in) ,∀k∈Ω ^(BH) R _(k) ^(BHR,out)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,out) ,∀k∈Ω ^(BH), where R_(k) ^(BHR,in) and R_(k) ^(BHR,out) represent an inlet carbon flow rate and an outlet carbon flow rate of a pipeline k in the water return network, respectively, unit: tCO₂/h; ρ_(k) ^(BHR) represents a carbon flow density of the pipeline k in the water return network, unit: tCO₂/h; m_(k) ^(R) represents a mass flow of the pipeline k in the water return network, unit: kg/h; and T_(k) ^(R,in) and T_(k) ^(R,out) represent an inlet temperature and an outlet temperature of the pipeline k in the water return network, unit: ° C.; determining the network loss carbon emission of the district heating system comprising a network loss carbon flow rate of the water supply network and a network loss carbon flow rate of the water return network, said determining the network loss carbon emission of the district heating system being: determining a temperature difference of a pipeline in the water supply network and a temperature difference of a pipeline in the water return network: T _(k) ^(S,Loss) =T _(k) ^(S,in) −T _(k) ^(S,out) T _(k) ^(R,Loss) =T _(k) ^(R,in) −T _(k) ^(R,out), where T_(k) ^(S,Loss) and T_(k) ^(R,Loss) represent a temperature difference between both ends of the pipeline k in the water supply network and a temperature difference between both ends of the pipeline k in the water return network, respectively, unit: ° C.; and determining the network loss carbon flow rate of the water supply network and the network loss carbon flow rate of the water return network: R _(k) ^(BHS,Loss)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,Loss) ,∀k∈Ω ^(BH) R _(k) ^(BHR,Loss)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,Loss) ,∀k∈Ω ^(BH), where R_(k) ^(BHS,Loss) and R_(k) ^(BHR,Loss) represent a network loss carbon flow rate of the pipeline k in the water supply network and a network loss carbon flow rate of the pipeline k in the water return network, respectively, unit: tCO₂/h; determining the nodal carbon flow density of the district heating system, said determining the nodal carbon flow density of the district heating system comprising: determining, for each node in the district heating system, that conservation of mass and conservation of energy are satisfied at the node: ${m_{n}^{S} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}m_{k}^{S}}},{\forall{n \in \Omega^{NH}}}$ ${{T_{n}^{S}m_{n}^{S}} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}{T_{k}^{S,{out}}m_{k}^{S}}}},{\forall{n \in \Omega^{NH}}},$ where m_(n) ^(S) represents a total mass flow flowing through a node n in the water supply network, unit: kg/h; Ω_(n) ^(BH+) represents a set of injection pipelines at the node n in the water supply network; Ω^(NH) represents a set of nodes in the district heating system; and T_(n) ^(S) represents a water flow temperature of the node n in the water supply network, unit: ° C.; determining, for each node in the district heating system, that conservation of carbon emission is satisfied at the node, a carbon flow rate of the node n being equal to a sum of outlet carbon flow rates of all the injection pipelines and network loss carbon flow rates allocated to the injection pipelines; ${R_{n}^{NHS} = {{\sum\limits_{k \in \Omega_{n}^{{BH} +}}\left( {R_{k}^{{BHS},{out}} + {XR}_{k}^{{BHS},{Loss}}} \right)} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}{\rho_{k}^{BHS}{{cm}_{k}^{S}\left( {T_{k}^{S,{out}} + {XT_{k}^{S,{Loss}}}} \right)}}}}},$ ∀n ∈ Ω^(NH), where R_(n) ^(NHS) represents the carbon flow rate of the node n in the water supply network, unit: tCO₂/h; and X represents an allocating coefficient of a network loss carbon flow rate of an injection pipeline; determining a carbon flow density of the node n in the water supply ${\rho_{n}^{NHS} = {\frac{R_{n}^{NHS}}{cm_{n}^{S}T_{n}^{S}} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{\rho_{k}^{BHS}{m_{k}^{S}\left( {T_{k}^{S,{out}} + {XT_{k}^{S,{Loss}}}} \right)}}}{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{m_{k}^{S}T_{k}^{S,{out}}}}}},{\forall{n \in \Omega^{NH}}},$ where R_(n) ^(NHS) represents the carbon flow density of the node n in the water supply network, unit: tCO₂/MWh; and determining a carbon flow density of the node n in the water return network: ${\rho_{n}^{NHR} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{\rho_{k}^{BHR}{m_{k}^{R}\left( {T_{k}^{R,{out}} + {XT}_{k}^{R,{Loss}}} \right)}}}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{m_{k}^{R}T_{k}^{R,{out}}}}},{\forall{n \in \Omega^{NH}}},$ where ρ_(n) ^(NHR) represents the carbon flow density of the node n in the water return network, unit: tCO₂/MWh; and Ω_(n) ^(BH−) represents a set of outflow pipelines at the node n in the water supply network; determining the pipeline carbon flow density of the district heating system: ρ_(k) ^(BHS)=ρ_(n) ^(NHS) ,n=Γ _(k) ^(NH+) ,∀k∈Ω ^(BH) ρ_(k) ^(BHR)=ρ_(n) ^(NHR) ,n=Γ _(k) ^(NH−) ,∀k∈Ω ^(BH), where Γ_(k) ^(NH+) and Γ_(k) ^(NH+) represent an injection node and an outflow node of the pipeline k in the water supply network, respectively; determining the heat source carbon flow rate of the district heating system, said determining the heat source carbon flow rate of the district heating system comprising: determining a heat output of a heat source: Q _(i) =cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(i) ^(NH) ,∀i∈Ω ^(GH), where Q_(i) represents a heat output of a heat source i, unit: MW; Γ_(i) ^(NH) represents a node where the heat source i is located; and Ω^(GH) represents a set of heat sources; and determining that conservation of carbon emission at a heat source node is satisfied: ρ_(n) ^(NHS) cm _(n) ^(S) T _(n) ^(S)=ρ_(i) ^(GH) Q _(i)+ρ_(n) ^(NHR) cm _(n) ^(S) T _(n) ^(R) ,n=Γ _(i) ^(NH) ,∀i∈ΩGH, where ρ_(i) ^(GH) represents a carbon flow density of the heat source i, unit: tCO₂/MWh; and determining the heat load carbon flow rate of the district heating system, said determining the heat load carbon flow rate of the district heating system comprising: determining a heat load demand: q _(j) =cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH), where q_(j) represents a heat demand of a heat load j, unit: MW; Γ_(j) ^(NH) represents a node where the heat load j is located; and Ω^(LH) represents a set of heat loads; determining a carbon flow density of a heat load node: ρ_(n) ^(NHR)=ρ_(n) ^(NHS) ,n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH); and determining the heat load carbon flow rate: R _(j) ^(LH)=ρ_(n) ^(NHS) q _(j)=ρ_(n) ^(NHS) cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH), where R_(j) ^(LH) represents a carbon flow rate of the heat load j, unit: tCO₂/h.
 11. The electronic device according to claim 10, further comprising: calculating a matrix representation of the steady carbon emission flow model of the district heating system.
 12. The electronic device according to claim 11, wherein said calculating the matrix representation of the steady carbon emission flow model of the district heating system comprises: constructing a branch heat flow matrix, a branch network loss matrix, and a nodal heat flow flux matrix of the district heating system; and calculating a nodal carbon flow density vector of a heat network, and then calculating a branch carbon flow rate matrix, a network loss carbon flow rate matrix, and a load carbon flow rate vector of each of the water supply network and the water return network.
 13. The electronic device according to claim 12, wherein said calculating the matrix representation of the steady carbon emission flow model of the district heating system comprises: constructing the branch heat flow matrix of the district heating system comprising a branch heat flow matrix of the water supply network and a branch heat flow matrix of the water return network, wherein said constructing the branch heat flow matrix of the district heating system comprises: determining elements of the branch heat flow matrix of the water supply network: Q _(B,ij) ^(S) =cm _(k) ^(S) T _(k) ^(S,out) ,Q _(B,ji) ^(S)=0, where Q_(B,ij) ^(S) and Q_(B,ji) ^(S) represent elements in a branch heat flow matrix Q_(B) ^(S) of the water supply network; and determining elements of the branch heat flow matrix of the water return network: Q _(B,ij) ^(R) =cm _(k) ^(R) T _(k) ^(R,out) ,Q _(B,ji) ^(R)=0, where Q_(B,ij) ^(R) and Q_(B,ji) ^(R) represent elements in a branch heat flow matrix Q_(B) ^(R) of the water return network; constructing the branch network loss matrix of the district heating system comprising a branch network loss matrix of the water supply network and a branch network loss matrix of the water return network, wherein said constructing the branch network loss matrix of the district heating system comprises: determining elements of the branch network loss matrix of the water supply network: Q _(BL,ij) ^(S) =cm _(k) ^(S) T _(k) ^(S,Loss) ,Q _(BL,ji) ^(S)=0, where Q_(BL,ij) ^(S) and Q_(BL,ji) ^(S) represent elements in a branch network loss matrix Q_(BL) ^(S) of the water supply network; and determining elements of the branch network loss matrix of the water return network: Q _(BL,ij) ^(R) =cm _(k) ^(R) T _(k) ^(R,Loss) ,Q _(BL,ji) ^(R)=0, where Q_(BL,ij) ^(R) and Q_(BL,ji) ^(R) represent elements in a branch network loss matrix Q_(BL) ^(R) of the water return network; constructing the nodal heat flow flux matrix of the district heating system comprising a nodal heat flow flux matrix of the water supply network and a nodal heat flow flux matrix of the water return network, wherein said constructing the nodal heat flow flux matrix of the district heating system comprises: determining, for a node in no connection to the heat source, the nodal heat flow flux matrix of the water supply network: Q _(N) ^(S)=diag{ζ_(N) _(NH) Q _(B) ^(S)}, where Q_(N) ^(S) represents the nodal heat flow flux matrix of the water supply network; ζ_(N) _(NH) represents a coefficient matrix of a branch heat flow; and N_(NH) represents a number of nodes of the district heating system; determining, for a node in no connection to the heat source, the nodal heat flow flux matrix of the water return network: Q _(N) ^(R)=diag{ζ_(N) _(NH) Q _(B) ^(R)}, where Q_(N) ^(R) represents the nodal heat flow flux matrix of the water return network; determining, for a node connected to the heat source, a nodal integrated energy flow flux matrix: {circumflex over (Q)} _(N) ^(S)=diag{ζ_(N) _(NH) Q _(B) ^(S)+ζ_(N) _(GH) Q _(G)}, where {circumflex over (Q)}_(N) ^(S) represents the nodal integrated energy flow flux matrix; ζ_(N) _(GH) represents a coefficient matrix of a heat flow injected by the heat source; and N_(GH) represents a number of heat sources of the district heating system; determining, for all nodes, that a total injected carbon emission of the nodes is equal to a sum of injected carbon flow rates of all branches connected to the nodes: Q _(N) ^(S)ρ^(NHS)=(Q _(B) ^(S) +XQ _(BL) ^(S))^(T)ρ^(NHS) Q _(N) ^(R)ρ^(NHR)=(Q _(B) ^(R) +XQ _(BL) ^(R))^(T)ρ^(NHR), where ρ^(NHS) represents a matrix formed by the carbon flow density ρ_(n) ^(NHS) of the node n in the water supply network; and ρ^(NHR) represents a matrix formed by the carbon flow density ρ_(n) ^(NHR) of the node n in the water return network; determining, for the heat load node, that the heat load node has an equal carbon flow density in the water supply network and the water return network: Bρ ^(NHS) =Bρ ^(NHR), where B represents a heat load-node association matrix, when the heat load j is connected to the node n, B_(jn)=1, otherwise B_(jn)=0; determining, for the heat source node, a matrix relation of the heat source node based on a conservation of carbon emission as: C{circumflex over (Q)} _(N) ^(S)ρ^(NHS) =CQ _(N) ^(R)ρ^(NHR) +Q _(G) ^(T)ρ^(GH), where C represents a 0-1 matrix associated with the heat source node, when the node n is connected to the heat source, C_(nn)=1, otherwise C_(nn)=0; determining the nodal carbon flow density vector of the heat network as: ${\begin{bmatrix} \rho^{NHS} \\ \rho^{NHR} \end{bmatrix} = {\begin{bmatrix} {Q_{N}^{S} - \left( {Q_{B}^{S} + {XQ_{BL}^{S}}} \right)^{T}} & 0 \\ 0 & {Q_{N}^{R} - \left( {Q_{B}^{R} + {XQ}_{BL}^{R}} \right)^{T}} \\ B & {- B} \\ {C{\overset{\hat{}}{Q}}_{N}^{S}} & {{- C}Q_{N}^{R}} \end{bmatrix}^{- 1}\begin{bmatrix} 0 \\ 0 \\ 0 \\ {Q_{G}^{T}\rho^{GH}} \end{bmatrix}}};$ calculating the branch carbon flow rate matrix, the network loss carbon flow rate matrix, and the load carbon flow rate vector of each of the water supply network and the water return network.
 14. The electronic device according to claim 13, further comprising: constructing the dynamic carbon emission flow model of the district heating system based on the water element carbon flow rates at the plurality of time periods, the actual outlet carbon flow rates of the pipeline at the plurality of time periods, the network loss carbon flow rates at the plurality of time periods, and the nodal carbon flow densities at the plurality of time periods, wherein said constructing the dynamic carbon emission flow model of the district heating system based on the water element carbon flow rates at the plurality of time periods, the actual outlet carbon flow rates of the pipeline at the plurality of time periods, the network loss carbon flow rates at the plurality of time periods, and the nodal carbon flow densities at the plurality of time periods is: determining the water element carbon flow rates at the plurality of time periods: ${{\overset{˜}{R}}_{k,t}^{{BHS},{out}} = {\frac{R_{k,{t - \delta_{k,t}}}^{{BHS},{in}}\left( {B_{k,t} - {\sigma M_{k}}} \right)}{\left( {m_{k,{t - \delta_{k,t}}}^{S}\Delta t} \right)} + {\sum\limits_{\tau = {t - \varphi_{k,t} + 1}}^{t - \delta_{k,t} - 1}R_{k,\tau}^{{BHS},{in}}} + \frac{R_{k,{t - \delta_{k,t}}}^{{BHS},{in}}\left( {{m_{k,t}^{S}\Delta t} + {\sigma M_{k}} - A_{k,t}} \right)}{\left( {m_{k,{t - \varphi_{k,t}}}^{S}\Delta t} \right)}}},$ where {tilde over (R)}_(k,t) ^(BHS,out) represents a water element carbon flow rate at a time period t; σ represents a density of water; M_(k) represents a volume of the pipeline k; φ_(k,t) represents an injection time period of an earliest water element component contained in a water flow flowing out of the pipeline k at the time period t; δ_(k,t) represents an injection time period of a latest water element component contained in the water flow flowing out of the pipeline k at the time period t; A_(k,t) represents a total injection water flow amount for φ_(k,t) time periods before the time period t; B_(k,t) represents a total injection water flow amount from a time period t−δ_(k,t) to the time period t; and expressions for A_(k,t) and B_(k,t) are: $A_{k,t} = \left\{ {\begin{matrix} {{\sum\limits_{\tau = {t - \varphi_{k,t} + 1}}^{t}{m_{k,\tau}^{S}\Delta t}},} & {\varphi_{k,t} \geq {\delta_{k,t} + 1}} \\ {B_{k,t},} & {\varphi_{k,t} < {\delta_{k,t} + 1}} \end{matrix},} \right.$ ${B_{k,t} = {\sum\limits_{\tau = {t - \delta_{k,t}}}^{t}{m_{k,\tau}^{S}\Delta t}}};$ determining the actual outlet carbon flow rates of the pipeline at the plurality of time periods and the network loss carbon flow rates at the plurality of time periods, said determining the actual outlet carbon flow rates of the pipeline at the plurality of time periods and the network loss carbon flow rates at the plurality of time periods comprising: calculating an actual temperature of an outlet water flow of the pipeline based on a conveying loss of the pipeline: ${T_{k,t}^{S,{out}} = {{\overset{˜}{T}}_{k,t}^{S,{out}}\exp\left( {- \frac{\lambda L_{k}}{{cm}_{k,t}^{S}}} \right)}},$ where T_(k,t) ^(S,out) represents the actual temperature of the outlet water flow of the pipeline; T_(k,t) ^(S,out) represents a weighted average of temperatures of injection water flows at previous time periods; λ represents a thermal conductivity coefficient of the pipeline; and L_(k) represents a length of the pipeline k; determining an actual outlet carbon flow rate of the pipeline at the time period t: R k , t BHS , out = R ~ k , t BHS , out ⁢ T k , t S , out T ~ k , t S , out ; and determining a network loss carbon flow rate of the pipeline at the time period t: ${R_{k,t}^{{BHS},{Loss}} = {{\overset{\sim}{R}}_{k,t}^{{BHS},{Loss}}\left( {1 - \frac{T_{k,t}^{S,{out}}}{{\overset{\sim}{T}}_{k,t}^{S,{out}}}} \right)}};$ determining the nodal carbon flow densities at the plurality of time periods: ${\rho_{n,t}^{NHS} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} +}}\left( {R_{k,t}^{{BHS},{out}} + {XR_{k,t}^{{BHS},{Loss}}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{cm_{k,t}^{S}T_{k,t}^{S,{out}}}}};$ determining, for the water return network, the nodal carbon flow densities at the plurality of time periods: $\rho_{n,t}^{NHS} = {\frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}\left( {R_{k,t}^{{BHS},{out}} + {XR}_{k,t}^{{BHS},{Loss}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{cm_{k,t}^{R}T_{k,t}^{R,{out}}}}.}$
 15. A computer-readable storage medium, having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method for measuring the carbon emission of the district heating system according to claim
 1. 16. The computer-readable storage medium according to claim 15, wherein the method further comprises: constructing the steady carbon emission flow model of the district heating system based on the pipeline carbon flow rate, the network loss carbon emission, the nodal carbon flow density, the pipeline carbon flow density, the heat source carbon flow rate, and the heat load carbon flow rate of the district heating system, wherein said constructing the steady carbon emission flow model of the district heating system based on the pipeline carbon flow rate, the network loss carbon emission, the nodal carbon flow density, the pipeline carbon flow density, the heat source carbon flow rate, and the heat load carbon flow rate of the district heating system is: determining the pipeline carbon flow rate of the district heating system comprising a carbon flow rate of a water supply network and a carbon flow rate of a water return network, the carbon flow rate of the water supply network being: R _(k) ^(BHS,in)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,in) ,∀k∈Ω ^(BH) R _(k) ^(BHS,out)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,out) ,∀k∈Ω ^(BH), where R_(k) ^(BHS,in) and R_(k) ^(BHS,out) represent an inlet carbon flow rate and an outlet carbon flow rate of a pipeline k in the water supply network, respectively, unit: tCO₂/h; ρ_(k) ^(BHS) represents a carbon flow density of the pipeline k in the water supply network, unit: tCO₂/MWh; c represents a specific heat capacity of water, unit: MWh/(kg·° C.); m_(k) ^(S) represents a mass flow of the pipeline k in the water supply network, unit: kg/h; T_(k) ^(S,in) and T_(k) ^(S,out) represent an inlet temperature and an outlet temperature of the pipeline k in the water supply network, unit: ° C.; and Ω^(BH) represents a set of pipelines in the district heating system; and the carbon flow rate of the water return network being: R _(k) ^(BHR,in)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,in) ,∀k∈Ω ^(BH) R _(k) ^(BHR,out)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,out) ,∀k∈Ω ^(BH), where R_(k) ^(BHR,in) and R_(k) ^(BHR,out) represent an inlet carbon flow rate and an outlet carbon flow rate of a pipeline k in the water return network, respectively, unit: tCO₂/h; ρ_(k) ^(BHR) represents a carbon flow density of the pipeline k in the water return network, unit: tCO₂/h; m_(k) ^(R) represents a mass flow of the pipeline k in the water return network, unit: kg/h; and T_(k) ^(R,in) and T_(k) ^(R,out) represent an inlet temperature and an outlet temperature of the pipeline k in the water return network, unit: ° C.; determining the network loss carbon emission of the district heating system comprising a network loss carbon flow rate of the water supply network and a network loss carbon flow rate of the water return network, said determining the network loss carbon emission of the district heating system being: determining a temperature difference of a pipeline in the water supply network and a temperature difference of a pipeline in the water return network: T _(k) ^(S,Loss) =T _(k) ^(S,in) −T _(k) ^(S,out) T _(k) ^(R,Loss) =T _(k) ^(R,in) −T _(k) ^(R,out) where T_(k) ^(S,Loss) and T_(k) ^(R,Loss) represent a temperature difference between both ends of the pipeline k in the water supply network and a temperature difference between both ends of the pipeline k in the water return network, respectively, unit: ° C.; and determining the network loss carbon flow rate of the water supply network and the network loss carbon flow rate of the water return network: R _(k) ^(BHS,Loss)=ρ_(k) ^(BHS) cm _(k) ^(S) T _(k) ^(S,Loss) ,∀k∈Ω ^(BH) R _(k) ^(BHR,Loss)=ρ_(k) ^(BHR) cm _(k) ^(R) T _(k) ^(R,Loss) ,∀k∈Ω ^(BH), where R_(k) ^(BHS,Loss) and R_(k) ^(BHR,Loss) represent a network loss carbon flow rate of the pipeline k in the water supply network and a network loss carbon flow rate of the pipeline k in the water return network, respectively, unit: tCO₂/h; determining the nodal carbon flow density of the district heating system, said determining the nodal carbon flow density of the district heating system comprising: determining, for each node in the district heating system, that conservation of mass and conservation of energy are satisfied at the node: ${m_{n}^{S} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}m_{k}^{S}}},{\forall{n \in \Omega^{NH}}}$ ${{T_{n}^{S}m_{n}^{S}} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}{T_{k}^{S,{out}}m_{k}^{S}}}},{\forall{n \in \Omega^{NH}}},$ where m_(n) ^(S) represents a total mass flow flowing through a node n in the water supply network, unit: kg/h; Ω_(n) ^(BH+) represents a set of injection pipelines at the node n in the water supply network; Ω^(NH) represents a set of nodes in the district heating system; and T_(n) ^(S) represents a water flow temperature of the node n in the water supply network, unit: ° C.; determining, for each node in the district heating system, that conservation of carbon emission is satisfied at the node, a carbon flow rate of the node n being equal to a sum of outlet carbon flow rates of all the injection pipelines and network loss carbon flow rates allocated to the injection pipelines; ${R_{n}^{NHS} = {{\sum\limits_{k \in \Omega_{n}^{{BH} +}}\left( {R_{k}^{{BHS},{out}} + {\lambda R_{k}^{{BHS},{Loss}}}} \right)} = {\sum\limits_{k \in \Omega_{n}^{{BH} +}}{\rho_{k}^{BHS}{{cm}_{k}^{S}\left( {T_{k}^{S,{out}} + {XT_{k}^{S,{Loss}}}} \right)}}}}},{\forall{n \in \Omega^{NH}}},$ where R_(n) ^(NHS) represents the carbon flow rate of the node n in the water supply network, unit: tCO₂/h; and X represents an allocating coefficient of a network loss carbon flow rate of an injection pipeline; determining a carbon flow density of the node n in the water supply network: ${\rho_{n}^{NHS} = {\frac{R_{n}^{NHS}}{cm_{n}^{S}T_{n}^{S}} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{\rho_{k}^{BHS}{m_{k}^{S}\left( {T_{k}^{S,{out}} + {XT_{k}^{S,{Loss}}}} \right)}}}{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{m_{k}^{S}T_{k}^{S,{out}}}}}},{\forall{n \in \Omega^{NH}}},$ where ρ_(n) ^(NHS) represents the carbon flow density of the node n in the water supply network, unit: tCO₂/MWh; and determining a carbon flow density of the node n in the water return network: ${\rho_{n}^{NHR} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{\rho_{k}^{BHR}{m_{k}^{R}\left( {T_{k}^{R,{out}} + {XT}_{k}^{R,{Loss}}} \right)}}}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{m_{k}^{R}T_{k}^{R,{out}}}}},{\forall{n \in \Omega^{NH}}},$ where ρ_(n) ^(NHR) represents the carbon flow density of the node n in the water return network, unit: tCO₂/MWh; and Ω_(n) ^(BH−) represents a set of outflow pipelines at the node n in the water supply network; determining the pipeline carbon flow density of the district heating system: ρ_(k) ^(BHS)=ρ_(n) ^(NHS) ,n=Γ _(k) ^(NH+) ,∀k∈Ω ^(BH) ρ_(k) ^(BHR)=ρ_(n) ^(NHR) ,n=Γ _(k) ^(NH−) ,∀k∈Ω ^(BH), where Γ_(k) ^(NH+) and Γ_(k) ^(NH+) represent an injection node and an outflow node of the pipeline k in the water supply network, respectively; determining the heat source carbon flow rate of the district heating system, said determining the heat source carbon flow rate of the district heating system comprising: determining a heat output of a heat source: Q _(i) =cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(i) ^(NH) ,∀i∈Ω ^(GH), where Q_(i) represents a heat output of a heat source i, unit: MW; Γ_(i) ^(NH) represents a node where the heat source i is located; and Ω^(GH) represents a set of heat sources; and determining that conservation of carbon emission at a heat source node is satisfied: ρ_(n) ^(NHS) cm _(n) ^(S) T _(n) ^(S)=ρ_(i) ^(GH) Q _(i)+ρ_(n) ^(NHR) cm _(n) ^(S) T _(n) ^(R) ,n=Γ _(i) ^(NH) ,∀i∈Ω ^(GH), where ρ_(i) ^(GH) represents a carbon flow density of the heat source i, unit: tCO₂/MWh; and determining the heat load carbon flow rate of the district heating system, said determining the heat load carbon flow rate of the district heating system comprising: determining a heat load demand: q _(j) =cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH), where q_(j) represents a heat demand of a heat load j, unit: MW; Γ_(j) ^(NH) represents a node where the heat load j is located; and Ω^(LH) represents a set of heat loads; determining a carbon flow density of a heat load node: ρ_(n) ^(NHR)=ρ_(n) ^(NHS) ,n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH); and determining the heat load carbon flow rate: R _(j) ^(LH)=ρ_(n) ^(NHS) q _(j)=ρ_(n) ^(NHS) cm _(n) ^(S)(T _(n) ^(S) −T _(n) ^(R)),n=Γ _(j) ^(NH) ,∀j∈Ω ^(LH), where R_(j) ^(LH) represents a carbon flow rate of the heat load j, unit: tCO₂/h.
 17. The computer-readable storage medium according to claim 16, wherein the method further comprises: calculating a matrix representation of the steady carbon emission flow model of the district heating system.
 18. The computer-readable storage medium according to claim 17, wherein said calculating the matrix representation of the steady carbon emission flow model of the district heating system comprises: constructing a branch heat flow matrix, a branch network loss matrix, and a nodal heat flow flux matrix of the district heating system; and calculating a nodal carbon flow density vector of a heat network, and then calculating a branch carbon flow rate matrix, a network loss carbon flow rate matrix, and a load carbon flow rate vector of each of the water supply network and the water return network.
 19. The computer-readable storage medium according to claim 18, wherein said calculating the matrix representation of the steady carbon emission flow model of the district heating system comprises: constructing the branch heat flow matrix of the district heating system comprising a branch heat flow matrix of the water supply network and a branch heat flow matrix of the water return network, wherein said constructing the branch heat flow matrix of the district heating system comprises: determining elements of the branch heat flow matrix of the water supply network: Q _(B,ij) ^(S) =cm _(k) ^(S) T _(k) ^(S,out) ,Q _(B,ji) ^(S)=0, where Q_(B,ij) ^(S) and Q_(B,ji) ^(S) represent elements in a branch heat flow matrix Q_(B) ^(S) of the water supply network; and determining elements of the branch heat flow matrix of the water return network: Q _(B,ij) ^(R) =cm _(k) ^(R) T _(k) ^(R,out) ,Q _(B,ji) ^(R)=0, where Q_(B,ij) ^(R) and Q_(B,ji) ^(R) represent elements in a branch heat flow matrix Q_(B) ^(R) of the water return network; constructing the branch network loss matrix of the district heating system comprising a branch network loss matrix of the water supply network and a branch network loss matrix of the water return network, wherein said constructing the branch network loss matrix of the district heating system comprises: determining elements of the branch network loss matrix of the water supply network: Q _(BL,ij) ^(S) =cm _(k) ^(S) T _(k) ^(S,Loss) ,Q _(BL,ji) ^(S)=0, where Q_(BL,ij) ^(S) and Q_(BL,ji) ^(S) represent elements in a branch network loss matrix Q_(BL) ^(S) of the water supply network; and determining elements of the branch network loss matrix of the water return network: Q _(BL,ij) ^(R) =cm _(k) ^(R) T _(k) ^(R,Loss) ,Q _(BL,ji) ^(R)=0, where Q_(BL,ij) ^(R) and Q_(BL,ji) ^(R) represent elements in a branch network loss matrix Q_(BL) ^(R) of the water return network; constructing the nodal heat flow flux matrix of the district heating system comprising a nodal heat flow flux matrix of the water supply network and a nodal heat flow flux matrix of the water return network, wherein said constructing the nodal heat flow flux matrix of the district heating system comprises: determining, for a node in no connection to the heat source, the nodal heat flow flux matrix of the water supply network: Q _(N) ^(S)=diag{ζ_(N) _(NH) Q _(B) ^(S)}, where Q_(N) ^(S) represents the nodal heat flow flux matrix of the water supply network; ζ_(N) _(NH) represents a coefficient matrix of a branch heat flow; and N_(NH) represents a number of nodes of the district heating system; determining, for a node in no connection to the heat source, the nodal heat flow flux matrix of the water return network: Q _(N) ^(R)=diag{ζ_(N) _(NH) Q _(B) ^(R)}, where Q_(N) ^(R) represents the nodal heat flow flux matrix of the water return network; determining, for a node connected to the heat source, a nodal integrated energy flow flux matrix: {circumflex over (Q)} _(N) ^(S)=diag{ζ_(N) _(NH) Q _(B) ^(S)+ζ_(N) _(GH) Q _(G)}, where {circumflex over (Q)}_(N) ^(S) represents the nodal integrated energy flow flux matrix; ζ_(N) _(GH) represents a coefficient matrix of a heat flow injected by the heat source; and N_(GH) represents a number of heat sources of the district heating system; determining, for all nodes, that a total injected carbon emission of the nodes is equal to a sum of injected carbon flow rates of all branches connected to the nodes: Q _(N) ^(S)ρ^(NHS)=(Q _(B) ^(S) +XQ _(BL) ^(S))^(T)ρ^(NHS) Q _(N) ^(R)ρ^(NHR)=(Q _(B) ^(R) +XQ _(BL) ^(R))^(T)ρ^(NHR), where ρ^(NHS) represents a matrix formed by the carbon flow density ρ_(n) ^(NHS) of the node n in the water supply network; and ρ^(NHR) represents a matrix formed by the carbon flow density ρ_(n) ^(NHR) of the node n in the water return network; determining, for the heat load node, that the heat load node has an equal carbon flow density in the water supply network and the water return network: Bρ ^(NHS) =Bρ ^(NHR), where B represents a heat load-node association matrix, when the heat load j is connected to the node n, B_(jn)=1, otherwise B_(jn)=0; determining, for the heat source node, a matrix relation of the heat source node based on a conservation of carbon emission as: C{circumflex over (Q)} _(N) ^(S)ρ^(NHS) =CQ _(N) ^(R)ρ^(NHR) +Q _(G) ^(T)σ^(GH), where C represents a 0-1 matrix associated with the heat source node, when the node n is connected to the heat source, C_(nn)=1, otherwise C_(nn)=0; determining the nodal carbon flow density vector of the heat network as: ${\begin{bmatrix} \rho^{NHS} \\ \rho^{NHR} \end{bmatrix} = {\begin{bmatrix} {Q_{N}^{S} - \left( Q_{B}^{S} \right.} & \left. {{+ X}Q_{BL}^{S}} \right)^{T} & 0 \\  & 0 & {Q_{N}^{R} - \left( {Q_{B}^{R} + {XQ_{BL}^{R}}} \right)^{T}} \\  & B & {- B} \\  & {C{\overset{\hat{}}{Q}}_{N}^{S}} & {{- C}Q_{N}^{R}} \end{bmatrix}^{- 1}\begin{bmatrix} 0 \\ 0 \\ 0 \\ {Q_{G}^{T}\rho^{GH}} \end{bmatrix}}};$ and calculating the branch carbon flow rate matrix, the network loss carbon flow rate matrix, and the load carbon flow rate vector of each of the water supply network and the water return network.
 20. The computer-readable storage medium according to claim 19, wherein the method further comprises: constructing the dynamic carbon emission flow model of the district heating system based on the water element carbon flow rates at the plurality of time periods, the actual outlet carbon flow rates of the pipeline at the plurality of time periods, the network loss carbon flow rates at the plurality of time periods, and the nodal carbon flow densities at the plurality of time periods, wherein said constructing the dynamic carbon emission flow model of the district heating system based on the water element carbon flow rates at the plurality of time periods, the actual outlet carbon flow rates of the pipeline at the plurality of time periods, the network loss carbon flow rates at the plurality of time periods, and the nodal carbon flow densities at the plurality of time periods is: determining the water element carbon flow rates at the plurality of time periods: ${{\overset{˜}{R}}_{k,t}^{{BHS},{out}} = {\frac{R_{k,{t - \delta_{k,t}}}^{{BHS},{in}}\left( {B_{k,t} - {\sigma M_{k}}} \right)}{\left( {m_{k,{t - \delta_{k,t}}}^{S}\Delta t} \right)} + {\sum\limits_{\tau = {l - \varphi_{k,t} + 1}}^{t - \delta_{k,t} - 1}R_{k,\tau}^{{BHS},{in}}} + \frac{R_{k,{t - \delta_{k,t}}}^{{BHS},{in}}\left( {{m_{k,t}^{S}\Delta t} + {\sigma M_{k}} - A_{k,t}} \right)}{\left( {m_{k,{t - \varphi_{k,t}}}^{S}\Delta t} \right)}}},$ where {tilde over (R)}_(k,t) ^(BHS,out) represents a water element carbon flow rate at a time period t; σ represents a density of water; M_(k) represents a volume of the pipeline k; φ_(k,t) represents an injection time period of an earliest water element component contained in a water flow flowing out of the pipeline k at the time period t; δ_(k,t) represents an injection time period of a latest water element component contained in the water flow flowing out of the pipeline k at the time period t; A_(k,t) represents a total injection water flow amount for φ_(k,t) time periods before the time period t; B_(k,t) represents a total injection water flow amount from a time period t−δ_(k,t) to the time period t; and expressions for A_(k,t) and B_(k,t) are: $A_{k,t} = \left\{ {\begin{matrix} {{\sum\limits_{\tau = {t - \varphi_{k,1} + 1}}^{t}{m_{k,\tau}^{S}\Delta t}},} & {\varphi_{k,t} \geq {\delta_{k,t} + 1}} \\ {B_{k,t},} & {\varphi_{k,t} < {\delta_{k,t} + 1}} \end{matrix},} \right.$ ${B_{k,t} = {\sum\limits_{\tau = {t - \delta_{k,t}}}^{t}{m_{k,\tau}^{S}\Delta t}}};$ determining the actual outlet carbon flow rates of the pipeline at the plurality of time periods and the network loss carbon flow rates at the plurality of time periods, said determining the actual outlet carbon flow rates of the pipeline at the plurality of time periods and the network loss carbon flow rates at the plurality of time periods comprising: calculating an actual temperature of an outlet water flow of the pipeline based on a conveying loss of the pipeline: ${T_{k,t}^{S,{out}} = {{\overset{˜}{T}}_{k,t}^{S,{out}}{\exp\left( {- \frac{\lambda L_{k}}{cm_{k,t}^{S}}} \right)}}},$ where T_(k,t) ^(S,out) represents the actual temperature of the outlet water flow of the pipeline; {acute over (T)}_(k,t) ^(S,out) represents a weighted average of temperatures of injection water flows at previous time periods; λ represents a thermal conductivity coefficient of the pipeline; and L_(k) represents a length of the pipeline k; determining an actual outlet carbon flow rate of the pipeline at the time period t: ${R_{k,t}^{{BHS},{out}} = {{\overset{\sim}{R}}_{k,t}^{{BHS},{out}}\frac{T_{k,t}^{S,{out}}}{{\overset{\sim}{T}}_{k,t}^{S,{out}}}}};$ and determining a network loss carbon flow rate of the pipeline at the time period t: ${R_{k,t}^{{BHS},{Loss}} = {{\overset{\sim}{R}}_{k,t}^{{BHS},{Loss}}\left( {1 - \frac{T_{k,t}^{S,{out}}}{{\overset{\sim}{T}}_{k,t}^{S,{out}}}} \right)}};$ determining the nodal carbon flow densities at the plurality of time periods: ${\rho_{n,t}^{NHS} = \frac{\sum\limits_{k \in \Omega_{n}^{{BH} +}}\left( {R_{k,t}^{{BHS},{out}} + {XR_{k,t}^{{BHS},{Loss}}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} +}}{cm_{k,t}^{S}T_{k,t}^{S,{out}}}}};$ and determining, for the water return network, the nodal carbon flow densities at the plurality of time periods: $\rho_{n,t}^{NHS} = {\frac{\sum\limits_{k \in \Omega_{n}^{{BH} -}}\left( {R_{k,t}^{{BHS},{out}} + {XR}_{k,t}^{{BHS},{Loss}}} \right)}{\sum\limits_{k \in \Omega_{n}^{{BH} -}}{cm_{k,t}^{R}T_{k,t}^{R,{out}}}}.}$ 